Differential response to isoproturon by two strains of Saccharomyces cerevisiae.

S. cerevisiae UE-ME3 grown in MB medium in the absence and presence of IPU show a similar growth profile and a stabilization of the biomass, non-protein thiols content, cell viability (cfu) and cell redox status estimated by GSH/GSSG ratio. This response seems depend on GR and G6PD activities increase, which probably activates the glutathione cycle, signs of adaptive response to phenylurea. However, S. cerevisiae IGC-4072 strain showed signs of cell death in the presence of IPU, exhibiting a more slowly growth profile, a decrease of dry weight and cell viability, as well as a significant increase of free radicals scavenger (DPPH) in presence of phenylurea, without significant changes of the GSH/GSSG ratio. As the value of the GSH/GSSG ratio is significant lower in IGC-4072 cells and GR activity undergoes a marked decrease in the presence of the IPU it is suspected that the worst IPU adaptive capacity displayed by this strain depends on a poor antioxidant power mediated by the glutathione

Saccharomyces cerevisiae UE-ME3 is a good strain for isoproturon biorremediation?

Isoproturon, an herbicide of pre- and pos-emergence of Autumn-Winter crops, persists occasionally in soil, groundwater and biological systems at levels above those established by European Directives. Saccharomyces cerevisiae UE-ME3 exposed in stationary phase to 50 and 100 mM isoproturon exhibit growth rates higher than control or exposed cells to 5 and 25 mM of this phenylurea. However, in S.cerevisiae UE-ME3 grown in the presence of 5 mM isoproturon, were observed a decrease of GSH/GSSG ratio, an increase of cytoplasmatic MDA level, GR and GPx activities, usual markers of cell damage and oxidative stress. Nevertheless, S.cerevisiae grown at 25, 50 and 100 mM isoproturon, have developed adaptive responses to this phenylurea by stabilization of its reducing environment, lipid peroxidation decrease and GR, GPx activities increase, events regulated by isoproturon level in culture medium, facts which suggest that this yeast strain can be useful on bioremediation

Stress, burnout and well-being in teaching profession: Portuguese studies

Professional satisfaction plays an important role in the way the human being develops his work. This is a complex and subjective concept since the same situation can be a source of satisfaction for one individual and the cause for dissatisfaction for another (Lammy, 2015). Professional satisfaction in teaching is associated with important variables such as self-esteem, physical and mental well-being, motivation, commitment, involvement, stress, absenteeism, success and professional achievement (Viveiros, 2011). When a teacher displays feelings of dissatisfaction and malaise, such feelings affect not only his fellow teachers but also the students. Such disinvestment and lack of motivation contribute directly to students' lack of interest in the classroom and, consequently, to a lower quality of the teaching and learning processes (Resende, 2003). According to Silva (2012), professional satisfaction has direct effects on teachers’ motivation, which in turn always influences in some way the students’ academic success and compromises teachers’ willingness to their work, both individually and in teams. Professional satisfaction thus contributes to a pleasant school climate, facilitating planning and collaborative practices among teachers in order to achieve educational success

Comparative study of toxicological effects of lindane and isoproturon pesticides in the Saccharomyces cerevisiae

Organochlorine insecticides and phenylurea herbicides such as lindane (hexachlorocyclo-hexane, γ-HCH) and isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea, IPU), used in agricultural applications for the pest and broad-leaved control, are often found in contaminated groundwater and surface water. Unfortunately, the toxicity of these pesticides in eukaryotic cells is still poorly understood. Saccharomyces cerevisiae is a promising eukaryotic organism for the toxicological evaluation of pollutants, because its metabolism is similar to that of high-level organisms. Thus the aim of this study was to compare the effects of two pesticides on yeast-cell viability and its antioxidant power. S. cerevisiae UE-ME3, a wild-type strain belonging to Oenology Laboratory of the University of Évora, grown in the presence of 50 μM γ-HCH and 100 μM IPU in 2% glucose and peptone deprivation medium (YED), at 28 °C were compared with control cells. CFU were determined at the end of the experiment and remaining cells disintegrated in 10 mM phosphate buffer pH 7.0 by sonication. Post-12,000 × g supernatant was used for determination of glutathione (GSH), glutathione disulphide (GSSG) and malondialdehyde (MDA) content and glutathione reductase (GR), glutathione peroxidase (GPx) and cytoplasmic catalase (CTT1) activity. The results showed that 50 μM γ-HCH exposures, in YED medium, did not affect cell viability, CTT1 activity, non-protein thiols (GSH + GSSG) and MDA content of S. cerevisiae. However, the 50 μM γ-HCH exposure caused a decrease in GSH/GSSG ratio, GR and GPx activity. In contrast, 100 μM IPU exposures caused an increase in the cell viability, (GSH + GSSG), GSH/GSSG ratio and GR activity. Additionally, there was a decrease in the MDA levels, GPx and CTT1 activity, under the same growth conditions. In conclusion, the presence of lindane, in YED medium, caused a reducing-oxidizing transition, a slowdown of the glutathione redox cycle without disturbing the survival of S. cerevisiae. However, the increase in the cell viability, the redox buffer power and the lipid peroxidation attenuation caused by IPU in nitrogen deprivation, appears to be due to the high regeneration capacity of GSH via GR activity, pointing out a possible use of isoproturon as nitrogen source

Sjögren's syndrome and its impact in the oral cavity

Sjögren's syndrome is an autoimmune disease that affects salivary gland tissue. Patients can show different degrees of phenotype that can vary from mild to severe systemic symptoms. So far, the etiopathogenesis of this condition is still not fully unraveled but it is believed that genetic and environmental factors are involved. The purpose is to understand the role of genetics on the appearance of the Sjögren's syndrome and describe the clinical signs that might alert for the presence of a patient with this condition. The most impacting oral manifestation is xerostomia. The role of the dental doctor in the diagnosis, treatment and oral rehabilitation of these patients, is crucial to ensure a good quality of life.info:eu-repo/semantics/publishedVersio

Efeitos de variáveis cognitivas, emocionais e atitudinais no rendimento a matemática

Several predictive variables have been proposed to explain achievement on mathematics, allowing for the anticipation of complexity and the combination of multiple variables. Some studies indicate the multifactorial nature of mathematical performance, combining the cognitive and affective dimensions of the individual and the teaching and learning processes of mathematics. The main objective of this study is to evaluate the impact of cognitive, emotional and attitudinal variables on math performance. The results highlight the need to look at mathematics achievement in the 4th year of school using a multivariate approach

Exposition of cork oak roots to cryptogein reduced the Infection by Phytophtora cinnamomi

The oomycete P. cinnamomi has been described as strong contributing factor to the decline of cork oak and holm oak stands occurring in the Iberian Peninsula. There are no eradication methods available against this pathogen

Alpha cinnamomin elicits a defence response against Phytophthora cinnamomi in Castanea sativa

Phytophthora cinnamomi and P. cambivora are considered as the causal agents of Castanea sativa ink disease. These soil-borne plant pathogens invade and destroy the root system leading to the death of the trees. Most Phytophthora species secrete elicitins, a group of unique highly conserved proteins that are able to enhance plant defence responses in a systemic acquired resistance manner against infection by several pathogens. A cluster of four elicitin genes was identified in P. cinnamomi. In previous works one of these elicitins, α- cinnamomin was shown to restrict the invasion of root cortical tissues by P. cinnamomi preventing vascular colonization in cork and holm oak. In the present work, roots of chestnut plantlets grown in vitro were allowed to absorb α-cinnamomin at 100 μg/ml for two days before being inoculated with P. cinnamomi. The effects of this elicitin on host-pathogen interaction were studied at histological and ultrastructural levels. P. cinnamomi was restricted to the outer cortex of 65% of the roots pre-treated with α-cinnamomin. In these roots, the vascular cylinders were free of pathogen. On the contrary, the pathogen reached the vascular cylinder, penetrating the phloem and xylem vessels in all non-treated assayed roots. The signs of pathogen degradation in the cortical parenchyma, mainly in the intercellular spaces, and the increase of a physical barrier in epidermal and sub-epidermal cell wall-media lamella and intercellular spaces by impregnation with phenol-like compounds strongly suggest that α-cinnamomin induced in chestnut defence reactions against P. cinnamomi