Yeast as a model system to study mechanisms regulating cisplatin sensitivity and resistance

Cisplatin is a highly effective chemotherapeutic drug used in the treatment of several tumors. It is a DNA-damaging agent that induces apoptosis of rapidly proliferating cells, an important factor underlying its therapeutic efficacy. Unfortunately, cellular resistance occurs often. A large fraction of tumor cells harbor mutations in p53, contributing to defects in apoptotic pathways and drug resistance. However, cisplatin-induced apoptosis can also occur in p53 deficient cells; thus, elucidation of the molecular mechanism involved will potentially yield new strategies to eliminate tumors that have defects in the p53 pathway. Most of the studies in this field have been conducted in cultured mammalian cells, not amenable to systematic genetic manipulation. Therefore, we aimed to establish a simplified model to study cisplatin-induced apoptosis using the yeast Saccharomyces cerevisiae. Our results indicate cisplatin induces an active form of cell death in yeast, as this process was partially dependent on new protein synthesis and did not lead to loss of membrane integrity. Preliminary studies of apoptotic markers revealed mitochondrial fragmentation and chromatin condensation after cisplatin exposure. Deletion of Yca1p, the yeast metacaspase, did not protect cells from cisplatin-induced cell death, although exposure of yeast cells to cisplatin resulted in an increase in proteolytic activity that was inhibited in vitro by MG132, a commonly used proteasome inhibitor. In vivo, co-incubation with MG132 increased resistance to cisplatin and, accordingly, yeast strains deficient in proteasome proteolytic activity were more resistant to cisplatin than wild type strains. Proteasome inhibitors induce apoptosis in various cell types, whereas in others they prevent apoptosis induced by different stimuli. Our results indicate inhibition of the proteasome protects from cisplatin-induced apoptosis in budding yeast. The molecular mechanism involved is under characterization.This work was funded by FEDER through the program “Programa Operacional Factores de Competitividade-COMPETE” and by FCT Pest-C/BIA/UI4050/2011 (Fundação para a Ciência e Tecnologia) through projects and FCOMP-01-0124-FEDER-007047

Taste panel quality evaluation of 'Hayward' kiwifruit of different origins

In Portugal, the regions of Entre-Douro e Minho and Beira Litoral have exceptional conditions for the production of good quality kiwifruit. However, demand exceeds local supply resulting in importation of kiwifruit from Italy, Chile and New Zealand. Taste panels were run in December, May and June to study the preferences of Portuguese consumers for 'Hayward' kiwifruit. In December, a comparison was made between kiwifruit from Portugal and Italy, in May between kiwifruit from Portugal and Chile and in June between kiwifruit from Portugal, Chile and New Zealand. Attributes assessed by panellists were: appearance, texture, flavour, sweetness and acidity. The same samples were analyzed for: weight, equatorial and longitudinal diameter, firmness, soluble solids (as measured by refractometer) and titratable acidity. In May, panellists preferred Portuguese kiwifruit, but in December and June the preference was not so clear. In December, Portuguese kiwifruit were not at the eating ripe stage and in June they were at the end of their storage life (bad appearance but better flavour, sweetness and texture)

Building a knowledge and learning society in Portugal - Adult students in technological schools and higher education institutions

Chapter in Merrill, Barbara (ed.) (2009) Learning to Change? The Role of Identity and Learning Careers in Adult Education. Hamburg: Peter Lang Publishers. URL: http://www.peterlang.com/ index.cfm?vID=58279&vLang=E&vHR=1&vUR=2&vUUR=1This chapter introduces a case study of adult students in Portugal. It was developed by the Portuguese partner of the PRILHE (Promoting Reflective Independent Learning in HE) project consortium. This was a project funded by the European Commission Socrates Adult Education Programme (113869-CP-1-2004-1-UK- GRUNDTVIG-G1PP). In Portugal, adults may choose Higher Education Institutions[1] (HEI) or Technological Schools (TS) to pursue their education. The case study shows that there are similarities and differences between students from TS and Universities, mostly related with the approaches students have to learning and the way teachers take into consideration these approaches. It seems that TS have “best practices” that could usefully be implemented by other institutions. The chapter is organised as follows: first, we contextualize LLL development as an element within the political objective of creation of a knowledge economy, especially in the context of the European Union's Lisbon Agenda, linking education with employment. The different access routes non-traditional adult students can take to access Universities in the Portuguese higher education (HE) system are then briefly described. The PRILHE project, its main objectives, the participant institutions in the consortium, and the methodology used to gather and analyse data are briefly explained. Finally, the results of the Portuguese case within this project are presented and discu

Refrigeration needs for sustainable preservation of horticultural products

Fresh horticultural products are highly perishable and need refrigeration for further preservation. Refrigeration needs energy consumption with consequent economical cost and damage for the environment. The objective of the present work was to use efficiently the refrigeration according to the product needs and time for consumption. Salicornia ramosissima and Sarcocornia perennis fresh branch tips, which are used for fresh salads, were stored at 1, 4 and 9 °C for up to 21 days. In both species, fresh tips were of good consumer acceptability for up to 14 days at 9°C. At 1 and 4 °C fresh tips could be stored in good conditions up to 21 days. For efficient use of energy in refrigeration of fresh salicornia and sarcocornia we conclude that if it is to put those products in the market earlier we can use the higher temperature for storage saving energy. Only for further storage we shall use the lower temperatures

Nitroso-redox balance: a key mechanism in the regulation of the myocardial function in health and disease

Given the close interaction between nitric oxide (NO) and reactive oxygen species (ROS) in biological systems and their especial relevance in regulating aspects of the cardiovascular physiology, the concept of “nitroso-redox balance” has arisen as a more comprehensive manner of interpreting the intracellular redox state. Nitroso-redox signaling pathways participate in numerous cardiovascular mechanisms, including myocardial contractility and relaxation, mitochondrial respiration, and endothelial function. Alterations of this balance are involved in numerous aspects of cardiovascular pathophysiology. NO and ROS generating mechanisms play a major role in both regulating and responding to the redox state of the cell, which targets calcium handling, contractile and vasoactive mechanisms. Thus, the nitroso-redox signaling pathway is critically important in cardiac physiology and pathophysiology, and consequently a fundamental therapeutic target. This article briefly addresses the cardiovascular implications of the biological balance between NO and ROS, and their relevance in the development of heart diseases.Dada la íntima interacción entre el óxido nítrico (NO) y las especies reactivas de oxigeno (ROS) en los sistemas biológicos, y su especial relevancia en la regulación de la fisiología cardiovascular, ha surgido el concepto de “balance nitroso-redox” como una forma más inclusiva para interpretar el estado redox intracelular. Las vías de señalización nitroso-redox participan en numerosos mecanismos cardiovasculares, tales como contractilidad y relajación miocárdica, respiración mitocondrial y función endotelial. Las alteraciones de este balance están involucradas en muchos aspectos de la fisiopatología cardiovascular. Los sistemas que producen NO y ROS juegan un rol clave tanto en la regulación como en la respuesta al estado redox de la célula, el cual afecta el manejo de calcio y mecanismos contráctiles y vasoactivos. Así, las vías de señalización nitroso-redox son claves para la fisiología y fisiopatología cardiaca, y consecuentemente son un blanco terapéutico fundamental. Este artículo aborda brevemente las implicaciones cardiovasculares del balance biológico entre NO y ROS, y su relevancia en el desarrollo de enfermedades cardiacas.Sociedad Argentina de Fisiologí