The exosome and human ribosome biogenesis

Exoribonucleases have many important functions in the cell including RNA processing, turnover and quality control. One of the key 3’-5’ exonucleases is the exosome, a multiprotein complex that has been extensively characterised in yeast. Many substrates that undergo maturation and/or degradation involving the yeast exosome have been identified and these include tRNAs, mRNAs, snRNAs, snoRNAs and rRNAs. By comparison, the human exosome is poorly understood and it is not clear whether functions of the yeast exosome are conserved in higher eukaryotes. We show that the human exosome has degradation functions including the turnover, but not the processing, of snoRNAs and the recycling of excised pre-rRNA fragments. We and others have shown that the human exosome also participates in pre-rRNA processing to form the mature 3’ end of 5.8S rRNA. Here we identify a novel role for the exosome in the processing of the pre-rRNA internal transcribed spacer 1 (ITS1). The small (18S) and large (5.8S and 28S) subunit rRNAs are co-transcribed as a single precursor. Processing of ITS1 is a key step in ribosome biogenesis as it separates 18S from the large subunit rRNAs and in higher eukaryotes it involves an additional processing step compared to yeast. We define alternative ITS1 processing pathways in human cells. In the major pathway, following an endonucleolytic cleavage to separate the small and large subunit rRNAs, the exosome, which is not involved in ITS1 processing in yeast, processes to within 25 nucleotides of the 3’ end of 18S. Our data highlight significant differences between the nucleases involved in ITS1 processing in yeast and humans. However, it appears that the roles of several yeast biogenesis factors are conserved in higher eukaryotes. Further, we have investigated mechanisms by which exonucleolytic processing of ITS1 may be regulated and suggest how this could be coordinated with the final maturation steps of the pre-40S complex.EThOS - Electronic Theses Online ServiceBBSRCWellcome TrustGBUnited Kingdo

VERSO LA SICUREZZA ALIMENTARE. FLUSSI DI ELEMENTI POTENZIALMENTE TOSSICI (EPT) DAL SUOLO ALLE COLTURE ALIMENTARI

Soil is the basis of the ecosystems and of our system of food production. Crops can uptake heavy metals and potentially toxic elements from the soil and store them in the roots or translocate them to the aerial parts. Excessive content of these elements in edible parts can produce toxic effects and, through the food chain and food consumption, result in a potential hazard for human health. In this study soils and plants (spring wheat, Triticum aestivum L. and maize, Zea mays L.) from a tannery district in North-East Italy were analyzed to determine the content of some major and micro-nutrients and potentially toxic elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, S, Zn, V). The soils of the area are moderately polluted; Cr is the most important inorganic contaminant, followed by Ni, Cu and V. Factor analysis evidenced that the contaminants are in part anthropogenic and in part geogenic. Major anthropogenic origin was detected for Cr, Ni (from industrial activities), Zn, Cu, Cd (from agriculture practices). Biological Absorption Coefficient (BAC) from soil to plant roots and Translocation factor (TF) within the plant were calculated; major nutrients (K, P, S) and some micronutrients (Cu, Zn, Mg, Mn) are easily absorbed and translocated, whilst other nutrients (Ca, Fe) and potentially toxic elements or micronutrients (Al, Cd, Cr, Ni, Pb, V) are not accumulated in the seeds of the two considered plants. However, the two edible species proved differently able to absorb and translocate elements, and this suggests to consider separately every species as potential PHEs transporter to the food chain and to humans. Cr concentrations in seeds and other aerial parts (stem and leaves) of the examined plants are higher than the values found for the same species and for other cereals grown on unpolluted soils. Comparing the Cr levels in edible parts with recommended dietary intake, besides other possible Cr sources (dust ingestion, water), there seems to be no health risk for animal breeding and population due to the consumption of wheat and maize grown in the area.Le sol est la base des écosystèmes et de notre système de production alimentaire. Les cultures peuvent absorber métaux lourds  et éléments potentiellement toxiques du sol et les stocker dans les racines ou les déplacer vers les parties aériennes. Un teneur excessive de ces éléments dans les parties comestibles peut produire des effets toxiques et, par la chaîne alimentaire, conduire à un danger potentiel pour la santé humaine. Dans cette étude, les sols et les végétaux (blé de printemps, Triticum aestivum L. et du maïs, Zea mays L.) d'un terroir agro-industriel dans le Nord-Est de l'Italie ont été analysés pour déterminer la teneur de certains éléments majeurs et micro-nutritives et potentiellement toxiques (Al , Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, S, Zn, V). Les sols de la région sont modérément polluées; Cr est le polluant le plus important, suivi par Ni, Cu et V. L’analyse factorielle a mis en évidence que les contaminants sont en partie d'origine anthropique et en partie géogénique. Origine anthropique a été détectée pour Cr, Ni (activités industrielles), Zn, Cu, Cd (à partir de pratiques agricoles). Le coefficient d'absorption biologique (BAC) du sol aux racines et le facteur de translocation (TF) des racines à la partie arienne  ont été calculés. Les principaux nutritives (K, P, S) et certains oligo-éléments (Cu, Zn, Mg, Mn) sont facilement absorbés et transloqués, tandis que d'autres nutritives (Ca, Fe) et des éléments potentiellement toxiques (Al, Cd, Cr, Ni, Pb, V) ne sont pas accumulés dans les graines des deux plantes considérées. Toutefois, les deux espèces comestibles sont différemment capable d'absorber et déplacer ces éléments. Cela suggère d'examiner séparément chaque espèce comme potentiel transporteur des métaux à la chaîne alimentaire et à l'homme. Cr concentrations dans les graines et autres parties aériennes (tiges et feuilles) des plantes examinées sont plus élevés que les valeurs trouvées pour les mêmes espèces et pour les autres céréales cultivées sur des sols non pollués. En comparant les teneurs en Cr dans les parties comestibles des plantes étudiées avec les apports du Cr conseillés, en plus d'autres possibles sources du Cr (ingestion de poussières et d'eau), il semble que il n’y a aucun risque sanitaire pour l'élevage et la population en raison de la consommation de blé et de maïs cultivés dans la région.Il suolo è la base degli ecosistemi e del nostro sistema di produzione alimentare. Le colture possono assorbire metalli pesanti ed elementi potenzialmente tossici dal suolo e accumularli nelle radici o traslocarli nelle parti epigee. Un contenuto eccessivo di questi elementi nelle parti commestibili può produrre effetti tossici e, attraverso la catena alimentare e il consumo di cibo, si traducono in un potenziale pericolo per la salute umana. In questo studio i suoli e piante (grano primaverile, Triticum aestivum L. e mais, Zea mays L.) provenienti da un distretto conciario nel Nord-Est d'Italia sono stati analizzati per determinare il contenuto di alcuni macro e micro-nutrienti e di altri elementi potenzialmente tossici (Al , Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, S, Zn, V). I suoli della zona sono moderatamente inquinati ed il Cr costituisce il più importante dei contaminanti inorganici, seguito da Ni, Cu V e l’analisi fattoriali ha evidenziato come tali contaminanti siano in parte di origine antropica e in parte geogenica. Sono di origine antropica Cr e Ni derivanti da attività industriali e Zn, Cu, Cd da pratiche agricole. Sono stati calcolati il Coefficiente Biologica di Adsorbimento (CBA) dal suolo alle radici e Fattore di Traslocazione (FT) all'interno della pianta. I principali macro nutrienti (K, P, S) e alcuni micronutrienti (Cu, Zn, Mg, Mn) sono facilmente adsorbiti e traslocati, mentre altri nutrienti (Ca, Fe) o elementi potenzialmente tossici o micronutrienti (Al, Cd, Cr, Ni, Pb, V) non hanno evidenziato accumulo nei semi delle due piante considerate. Tuttavia, le due specie commestibili hanno evidenziato un diverso in grado di assorbimento e di traslocazione degli elementi, e questo suggerisce di considerare separatamente le varie specie vegetali in funzione della possibilità di traslocazione di elementi potenzialmente tossici nella catena alimentare e per l'uomo. Concentrazioni di Cr nei semi e altre parti aeree (fusto e foglie) delle piante esaminate sono risultati superiori ai valori trovati per le stesse specie e per altri cereali coltivati su suoli non inquinati. Tuttavia se si confrontano i livelli di Cr presenti nelle parti commestibili dei vegetali indagati con i valori di assunzione giornaliera raccomandata, a cui si possono aggiungere eventuali contributi da altre fonti (es.: ingestione di polvere, acqua), non sembra esserci nella zona indagata rischio per la salute degli animali e della popolazione in funzione del consumo del grano e del mais coltivati

A GIS – based methodology for land suitability evaluation in Veneto (NE Italy).

Since almost ten years, the Soil Science Research Group in Venice is carrying out studies on the characterization of soils in the Veneto region and their suitability for specific uses. Several areas have been investigated with the aim to select the best land use for a sustainable environment. The scenarios taken into consideration range from the Alpine and pre – Alpine region to the alluvial plain. Attention has been focused especially to land suitability for forestry, typical and niche crops, pasture and vineyard. The land evaluation procedure has been applied by a GIS – based methodology. Today, the GIS techniques are essential for the success of a correct and fast work, concerning the interpretation and processing of soil data and its display in form of map. Integrating information with crop and soil requirements, by means of "matching tables", it was possible to edit and manage land suitability maps for specific purposes. The applied methodology proved a useful and effective tool for sustainable land management

The design of novel microwave-heated reaction cells for infrared spectroscopy

Two novel microreactor cells for the investigation of catalysts by in-situ infrared spectroscopy under microwave and conventional heating are presented. A transmission infrared microreactor cell is demonstrated which holds a pressed catalyst disc in a controlled atmosphere and allows study of reactions from ambient temperatures to over 473 K. A cell that allows diffuse reflectance spectroscopy under reaction conditions up to 373 K under microwave heating and 423 K under conventional heating is also described. The optical characteristics of these cells are determined by the choice of CaF2 as the window material, allowing transmission from 77000-1110 cm−1. An oscillating microwave power heating regime was used to study the oxidation of carbon monoxide in air over the supported platinum catalysts EUROPT-1 and EUROPT-3, and their support oxides in these cells. The reaction was followed by time-resolved infrared spectroscopy and mass spectrometry. Both displayed a number of features that oscillated with the same frequency as the microwave perturbation. Production of CO2 appeared to vary with temperature in the same manner whether the catalysts were heated conventionally or with microwave radiation. Although no specific microwave effect for this reaction was observed, accurate thermometry within the cells was limited through the constraints imposed by microwave heating. Preliminary infrared emission and liquid phase experiments using the transmission cell are also reported.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

LANDSCAPE EVOLUTION AND GLOBAL SOIL CHANGE IN ALPINE VALLEYS: IMPACT OF ANTHROPEDOGENESIS ON TERRACED SOILS (BELLUNO, NORTHERN ITALY)

During the last decades, increasing human influence on the environment has determined strong impacts on soils. Although the effects of global soil change are currently quantified, to study and understand how and at which intensity soils are modified by human activity is of capital importance in order to effectively manage the changing ecosystems. One of the most important man-induced land transformations since many centuries is the terraced landform, an agricultural technique that characterizes many agro-ecosystems all over the world. In this study, our objectives were: i) to assess and compare the morphology and the physical-chemical-biological soil parameters of 'natural' and terraced soils; ii) to identify new forms and processes of anthropedogenesis in relation to chronological scales of human action operating within the natural pedogenesis time scales; iii) to use the existing taxonomic models for the classification of the terraced soils investigated

Assessment of total soil and plant elements in rice-based production systems in NE Italy

Macro- and micronutrients concentrations and PTEs contents in soils and plants (rice) fromthe rice district in the Venetian territory (NE Italy) have been determined by Inductive Coupled Plasma Optical Emission Spectrometry (ICP-OES), with the following aims: - to determine the background levels of macro- and microelements in the study area; - to assess possible contamination of soils and plants; - to calculate the Translocation Factor (TF) of metals from soil to plant, and the possible hazard for human health. Four rice plots with different rotation systems were investigated from seedling time to harvesting; sampling of soils (0–30 cm) and plants was carried out 4 times during growing season (three replicates). Rice plants were separated into the roots, stems, leaves and grains, and then oven-dried. Chemical and physical analyses were carried out at the Soil Science Lab of the University of Bologna and Venice, respectively. The results obtained point to a land with high soil contamination by Li and TI. The total concentrations of most studied metals (Al, As, Be, Cd, Co, Cr, Cu, Fe, Ni, Pb, Sb, Sn, Sr, V, Zn) in the soil samples fell in the natural geochemical background concentration levels, even though the concentration levels of some of them (e.g. Sn) overcame the Italian threshold limits for green areas (DM 152/2006). Most elements are likely associated with the geochemistry of the parent material. Antimony and Ti contents in soils are positively correlated with soil pH, while As, Be, Fe, Li, Sb, Ti, Tl and Zn are negatively correlated with organic matter content. With the exception of strontium, soil metals are always correlated between variable couples. Heavy metals in plants vary according to the sampling season, texture and moisture, and soil pH. Most non-essential trace elements are accumulated in rice roots and, only in cases of essential micronutrients, in leaves. Therefore, rice can be assumed as an excluder plant (i.e. metal in the roots b metal in soil) for Li, Sn, Tl. The results of multiple linear regression analysis showed that soil extractable P and total Ca played an important role in predicting annual grain yield of rice. The average translocation of metals from the soil to the root was found to be N1, irrespective of the essential/not essential function; conversely, only essential elements (Cu, Fe, Mn, Zn) are translocated rather easily from the roots to leaves (TF ≤ 1) via xylem, and very little are translocated to grains (TF ≪1). Rice plants were able to accumulate non essential metals in their tissues especially in the roots, but not in the edible part, and this could be useful for the restoration of contaminated sites with a very limited hazard for human population consuming rice crops

Assessment of total soil and plant trace elements in rice-based production systems in NE Italy

Recently, the widespread interest on soil enzymes is due to the need to develop sensitive indicators of soil quality that reflect the effects of land management on soil and assist land managers in promoting long-term sustainability of terrestrial ecosystems. The activities of six important enzymes involved in C, N, P, and S cycling were investigated in a paddy soil from the Veneto region, Italy, in four different rotation systems (rice-rice-rice, soya-rice-rice, fallow-rice and pea-soya-rice) with three replications in April (after field preparation, field moist condition), June (after seedling, waterlogged soil condition), August (after tillering stage of rice, waterlogged soil condition) and October (after rice harvesting, drained soil condition) over the 2012 growing season. Our results demonstrated that soil enzyme activities varied with rotation systems and growth stages in paddy field. Compared with field moist soil, drained soil condition resulted in a significant increase (P < 0.05) of β-glucosidase, arylsulfatase, alkaline and acid phosphatases, leucine aminopeptidase (except of F-R), and chitinase activities in all rotations, while compared with drained soil, waterlogging (in month of June, the early period of waterlogging) significantly decreased (P<0.05) β-glucosidase, alkaline and acid phosphatases, leucine aminopeptidase (except of P-S-R), arylsulfatase, chitinases. Soil organic-C was positively correlated with acid and alkaline phosphatases, and arylsulfatase while ß-glucosidase, chitinases and leucine aminopeptidase were not significantly correlated to soil organic-C. Enzyme activities were always correlated among them

Assessment of total soil and plant trace elements in rice-based production systems in NE Italy

Recently, the widespread interest on soil enzymes is due to the need to develop sensitive indicators of soil quality that reflect the effects of land management on soil and assist land managers in promoting long-term sustainability of terrestrial ecosystems. The activities of six important enzymes involved in C, N, P, and S cycling were investigated in a paddy soil from the Veneto region, Italy, in four different rotation systems (rice-rice-rice, soya-rice-rice, fallow-rice and pea-soya-rice) with three replications in April (after field preparation, field moist condition), June (after seedling, waterlogged soil condition), August (after tillering stage of rice, waterlogged soil condition) and October (after rice harvesting, drained soil condition) over the 2012 growing season. Our results demonstrated that soil enzyme activities varied with rotation systems and growth stages in paddy field. Compared with field moist soil, drained soil condition resulted in a significant increase (P < 0.05) of β-glucosidase, arylsulfatase, alkaline and acid phosphatases, leucine aminopeptidase (except of F-R), and chitinase activities in all rotations, while compared with drained soil, waterlogging (in month of June, the early period of waterlogging) significantly decreased (P<0.05) β-glucosidase, alkaline and acid phosphatases, leucine aminopeptidase (except of P-S-R), arylsulfatase, chitinases. Soil organic-C was positively correlated with acid and alkaline phosphatases, and arylsulfatase while ß-glucosidase, chitinases and leucine aminopeptidase were not significantly correlated to soil organic-C. Enzyme activities were always correlated among them

Assessment of total soil and plant trace elements in rice-based production systems in NE Italy

Recently, the widespread interest on soil enzymes is due to the need to develop sensitive indicators of soil quality that reflect the effects of land management on soil and assist land managers in promoting long-term sustainability of terrestrial ecosystems. The activities of six important enzymes involved in C, N, P, and S cycling were investigated in a paddy soil from the Veneto region, Italy, in four different rotation systems (rice-rice-rice, soya-rice-rice, fallow-rice and pea-soya-rice) with three replications in April (after field preparation, field moist condition), June (after seedling, waterlogged soil condition), August (after tillering stage of rice, waterlogged soil condition) and October (after rice harvesting, drained soil condition) over the 2012 growing season. Our results demonstrated that soil enzyme activities varied with rotation systems and growth stages in paddy field. Compared with field moist soil, drained soil condition resulted in a significant increase (P < 0.05) of β-glucosidase, arylsulfatase, alkaline and acid phosphatases, leucine aminopeptidase (except of F-R), and chitinase activities in all rotations, while compared with drained soil, waterlogging (in month of June, the early period of waterlogging) significantly decreased (P<0.05) β-glucosidase, alkaline and acid phosphatases, leucine aminopeptidase (except of P-S-R), arylsulfatase, chitinases. Soil organic-C was positively correlated with acid and alkaline phosphatases, and arylsulfatase while ß-glucosidase, chitinases and leucine aminopeptidase were not significantly correlated to soil organic-C. Enzyme activities were always correlated among them