Blocking variant surface glycoprotein synthesis in Trypanosoma brucei triggers a general arrest in translation initiation.

BACKGROUND: The African trypanosome Trypanosoma brucei is covered with a dense layer of Variant Surface Glycoprotein (VSG), which protects it from lysis by host complement via the alternative pathway in the mammalian bloodstream. Blocking VSG synthesis by the induction of VSG RNAi triggers an unusually precise precytokinesis cell-cycle arrest. METHODOLOGY/PRINCIPAL FINDINGS: Here, we characterise the cells arrested after the induction of VSG RNAi. We were able to rescue the VSG221 RNAi induced cell-cycle arrest through expression of a second different VSG (VSG117 which is not recognised by the VSG221 RNAi) from the VSG221 expression site. Metabolic labeling of the arrested cells showed that blocking VSG synthesis triggered a global translation arrest, with total protein synthesis reduced to less than 1-4% normal levels within 24 hours of induction of VSG RNAi. Analysis by electron microscopy showed that the translation arrest was coupled with rapid disassociation of ribosomes from the endoplasmic reticulum. Polysome analysis showed a drastic decrease in polysomes in the arrested cells. No major changes were found in levels of transcription, total RNA transcript levels or global amino acid concentrations in the arrested cells. CONCLUSIONS: The cell-cycle arrest phenotype triggered by the induction of VSG221 RNAi is not caused by siRNA toxicity, as this arrest can be alleviated if a second different VSG is inserted downstream of the active VSG221 expression site promoter. Analysis of polysomes in the stalled cells showed that the translation arrest is mediated at the level of translation initiation rather than elongation. The cell-cycle arrest induced in the presence of a VSG synthesis block is reversible, suggesting that VSG synthesis and/or trafficking to the cell surface could be monitored during the cell-cycle as part of a specific cell-cycle checkpoint

XXIV. mezinárodní kolokvium o regionálních vědách

Title in English: 24th International Colloquium on Regional Sciences: Conference proceedings. The conference proceedings consists of papers presented at the 24rd International Colloquium on Regional Sciences that was organized by Department of Regional Economics and Administration FEA MU. It contains 79 articles arranged by topic. The individual articles deal with e.g. socioeconomic disparities among regions, regional policy, territory attractiveness, tourism or regional public administration

Geomorphological Processes at the Industrial Sludge Landfill in Sered, Slovakia

The principal aim of the study is to identify the nature and causes of changes to the surface of a landfill body of waste from nickel production located in the industrial zone of the town of Sereď (Slovak Republic). This change is related to natural and anthropogenic geomorphological processes characteristic of the temperate zone of the northern hemisphere. The landfill is an accumulative anthropogenic form of relief, and its body is composed from an artefact-metallurgical sludge, which has specific properties. The landfill constitutes a strange shape of relief at the Danubian Plane, which attracts attention with its physiognomy and also with the black color of the material significantly. It formed during the 30-year-long existence of the nickel smelter plant (1963–1993) and remained in this location, until the present day, for another 28 years after the end of production. Since 1994, the landfill has been the property of a private company that mines sludge in order to obtain residual metals

The Nature of the Technosols on the Waste from Nickel Production

The aim of the study was to investigate the properties of the metallurgical sludge—waste from nickel production—on the landfill of a former nickel plant in Sereď, Slovakia, in relation to the technosols soil group. The sludge is a loose material which is a toxic industrial technological anthropogenic sediment of an unnatural black colour which originated from the crushing, washing, and leaching of poor iron–nickel lateritic ore in ammoniac solution and other caustics substances. The terrain reconnaissance enabled us to identify the points for the location of the probes. Here we dug seven probes and took 17 samples. In the samples the pH levels, the content of heavy metal and iron TOC, IC, C, and N, and the C:N ratio were determined. This study provides substantial empirical data on the properties of the metallurgical sludge. The results of the analyses clearly demonstrate that the sludge is a strongly alkaline material and contains toxic amounts of heavy metals (Cr, Ni). It is an artefact whose properties are unfavourable to living organisms and their communities. On the basis of the results of the probes analysis we identified the nature of the technosols on the given locality

Quality of life of Roma community in the Levoča city

The Slovak republic belongs to the most ethnically diverse countries in the central and eastern Europe. Based on the 2001 census it is evident that there are members of 17 different nationalities living in this country. The Romany community is the second largest national minority (preceded by Hungarians); and if the present natality trend continues they could become the majority population by 2060. There is a presumption that the highest number of Romanies, as high as 2 millions, live in Romania. Another most numerous Roma minorities are in Hungary and Bulgaria (about 800 000, MICHAELI a kol. 2002). The Romanies are a specific group of people when considering various aspects including the European origin and absence of a state domicile. The Romany population is a specific ethnic group presenting a community that is distant from the majority community with a different level of integration of individual groups with the majority community. (MATLOVIČ, 2005)

Optimising Potato (Solanum tuberosum L.) Cultivation by Selection of Proper Soils

This paper presents an attempt to differentiate the Slovak rural landscape with respect to the possibility of effective potato cultivation and to characterise soil parameters of current potato cultivation areas with the aim to increase the sustainability of the potato production. The selection was based on soil climatic, production and economic parameters. By using the GIS tools and existing databases on soil characteristics in Slovakia, maps of soil suitability categories for potato cultivation were generated. In Slovakia, it was found that 12.3% of farmland is very suitable for potato cultivation and that as much as 43.1% is not suitable. Later, the specified categories were characterised in detail and specified with respect to geographic, soil, climatic, production and economic parameters. Currently, most potato crops are cultivated on Cambisols (27%), Chernozems (20%) and Fluvisols (18%). Loamy soils (content of particles <0.01 mm is 30–45%), soils without gravel (gravel content in the depth 0.0–0.6 m is <10%), deep soils (>0.6 m) and soil situated on plains (slope 0°–3°) are dominant in these regions. We suggest that potato cultivation should be concentrated on the most suitable areas, thereby increasing the economic profitability, improving the ecological stability of the country and supporting the sustainability of the agriculture

Aplicaciones emergentes de inteligencia competitiva en las universidades

Different authors have pointed out the importance of applying competitive intelligence (CI) to non-business sectors (public administration, universities, non-governmental organizations, etc.). Besides, universities increasingly apply management tools and techniques coming from the business field. On the other hand, in recent years universities have perceived an environmental pressure as a consequence of a) their implication in regional development where they are located, and b) their need to reform their program offerings according to the needs of society and the requirements of the labour market, as well as a result of the process of adapting their degrees to the European Higher Education Area (Bologna process). This paper describes and characterises CI practices in the universities and analyses the CIcontribution to the design of degree courses. The research is based on qualitative methods, and data were collected through interviews. Results suggest that the use of CI in universities is mainly reactive, and addressed only to organisational tactics