63 research outputs found

    Analysis by RNA-seq of transcriptomic changes elicited by heat shock in Leishmania major

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    Besides their medical relevance, Leishmania is an adequate model for studying post-transcriptional mechanisms of gene expression. In this microorganism, mRNA degradation/stabilization mechanisms together with translational control and post-translational modifications of proteins are the major drivers of gene expression. Leishmania parasites develop as promastigotes in sandflies and as amastigotes in mammalians, and during host transmission, the parasite experiences a sudden temperature increase. Here, changes in the transcriptome of Leishmania major promastigotes after a moderate heat shock were analysed by RNA-seq. Several of the up-regulated transcripts code for heat shock proteins, other for proteins previously reported to be amastigote-specific and many for hypothetical proteins. Many of the transcripts experiencing a decrease in their steady-state levels code for transporters, proteins involved in RNA metabolism or translational factors. In addition, putative long noncoding RNAs were identified among the differentially expressed transcripts. Finally, temperature-dependent changes in the selection of the spliced leader addition sites were inferred from the RNA-seq data, and particular cases were further validated by RT-PCR and Northern blotting. This study provides new insights into the post-transcriptional mechanisms by which Leishmania modulate gene expressionThis work was supported by grants (to B.A. and J.M.R.) from Ministerio de Economía, Industria y Competitividad, project number SAF2017-86965-R (co-funded with FEDER funds), and by the Network of Tropical Diseases Research RICET (RD16/0027/0008), co-funded with FEDER funds. The CBMSO receives institutional grants from the Fundación Ramón Areces and from the Fundación Banco de Santande

    Stabilization of encapsulated probiotics from the bacterium Lactobacillus casei by different drying techniques

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    [EN] The main objective of this work is to encapsulate and dry the bacterium probiotic Lactobacillus casei applying three different drying techniques (lyophilization, fluidized bed and flash freeze drying) as well as to evaluate their viability during storage in the dark at 20ºC and 34% relative humidity for 28 days. In addition, to compare viability of the bacterium processed with flash freeze drying with cryoprotectant (skim milk) and without cryoprotectant. In the case of flash freeze drying, the final level of viability shows the potential of this drying technique with much less operating costs than lyophilization.The authors thank for technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF), and the Ministery of Higher Education, Science and Technology and FONDOCYT of the Dominican Republic.Acosta-Piantini, E.; Villaran, M.; Lombraña, JI. (2018). Stabilization of encapsulated probiotics from the bacterium Lactobacillus casei by different drying techniques. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 691-698. https://doi.org/10.4995/IDS2018.2018.7744OCS69169

    Microwave drying in fluidized bed to dehydrate microencapsulated Saccharomyces cerevisiae cells. Temperature control strategies

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    [EN] Alginate microcapsules containing cell yeasts of the species Saccharomyces cerivisae, used as a reference microorganism, were studied here to improve the protection of cell activity during food processing. Here a novel drying process was proposed to optimize processing conditions. The dehydration of microcapsules by microwaves and under near fluidizing conditions (NFMD), allows performing dehydration employing lower temperatures to maintain high viability levels and a high quality end product. Thus, strategies based on the combination of different thermal gradients and processing temperatures were analysed through a series of NFMD experiments.Mardaras, J.; Lombraña, JI.; Villarán, MC. (2018). Microwave drying in fluidized bed to dehydrate microencapsulated Saccharomyces cerevisiae cells. Temperature control strategies. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 1895-1902. https://doi.org/10.4995/IDS2018.2018.7854OCS1895190

    Domestic grape germination behaviour: the ‘Chardonnay’ and ‘Syrah’international cultivars’s study case

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    The domestic grape germination eco-physiology is a little studied aspect since reproduction occurs predominantly agamically, despite the sexual reproduction remains the main form for the selection of new cultivars. In this study, two international cultivars grown all over the world-Chardonnay and Syrah-were chosen as models of the domestic grape for the experiments in the eco-physiology of germination. The experimental design consisted of chemical, mechanical pre-treatments and combination of them as the bird ingestion pre-treatment that simulates the transit through the digestive tract of birds. Furthermore, seeds were submitted to different periods of cold stratification -0, 15, 30, 60 and 90 days -to simulate the winter effect. Seeds were placed to germinate at different incubation temperatures, to find the optimal germination protocol. The results showed that domestic grapes retain the need for cold stratification, and the best germination temperature is represented by the fluctuating temperature that simulates spring conditions. Our results help to understand what the best germination conditions of domestic grapes are and offer a contribution to extend the knowledge on how the process of domestication may have affected the biology of Vitis vinifera L. subsp. vinifera

    Effect of storage conditions on seed germination of eigTyrrhenian endemic vascular plant species of conservation interest

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    The conservation of endemic and endangered plant species is of great interest to the scientific and research community. In this frame, seed banks play a crucial role when biodiversity preservation and climate change are considered. The study of seed viability and germination during storage conditions provides basic and useful information to ensure successful ex situ conservation. The aim of this study was to evaluate whether storage time and conditions (i.e., base collection at -25°C and active collection at +5°C) affect seed germination in the long term. For these purposes, eight Tyrrhenian endemic vascular plant species (mostly endangered) with orthodox seeds were studied: Brassica insularis, Centranthus amazonum, Dianthus morisianus, Digitalis purpurea var. gyspergerae, Ferula arrigonii, Helicodiceros muscivorus, Iberis integerrima and Verbascum plantagineum. These species were stored in the Sardinian Germplasm Bank (BG-SAR) at -25°C and at +5°C for a time ranging from 2 to 12 years. Germination tests were carried out following the optimal conditions reported in the literature for each species. The results showed, in general terms, the high seed germination capacity of all species stored at both conditions; regarding the time of seed storage, germination in some tested species (such as B. insularis and C. amazonum) slightly decreased over time. We argued that seed dehydration, low seed moisture content during storage and the use of hermetic glass containers can be considered key factors for long-term conservation of these orthodox seeds. In conclusion, this study showed that the conservation of these endemic species is ensured by seed bank storage, according to the general assumption that seed longevity depends on seed lot quality, on well-sealed storage containers and conditions before and during storage

    Combining Different Approaches for Grape Pomace Valorization: Polyphenols Extraction and Composting of the Exhausted Biomass

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    Grape pomace represents 60%, by weight, of the solid side-streams of the wine-making process. The quantities produced, seasonality, and the presence of polyphenols pose economic and environmental issues that require proper management approaches based on the principles of sustainability and circular economy. The present work focuses on the combined application of solid-liquid extraction of polyphenols from ground grape pomace using a hydroethanolic mixture and the composting of the exhausted pomace. The obtained results support the possibility of recovering approximately 76.5 g of extract per kg of dry grape pomace (or 1.8 g of total phenols per kg of dry grape pomace). The composting process was not affected by the extraction process. On the contrary, the composting process was enhanced by the pomace particle size reduction, in terms of final biostability and content of humic acids

    The Mediterranean Island Wetlands (MedIsWet) inventory: strengths and shortfalls of the currently available floristic data

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    MedIsWet (Conservation of the island wetlands of the Mediterranean Basin) is a MAVA funded project which aims at investigating all seasonal or permanent island wetlands both natural and artificial, with a minimum extent of 0.1 hectares. More than 16,000 wetlands from almost all the Mediterranean, including islands from France, Italy, Malta, Croatia, Cyprus, Tunisia, Turkey, Greece and Spain were mapped. Over 2,500 of them were inventoried in the field and more than 500 scientific contributions catalogued. In total, more than 35,000 plant occurrences were uploaded, in a standardised and comparable way, on the national open-source web portals. These can be related to the recorded threats, uses and other spatially retrievable information. Here, we show strengths and shortfalls of the already available information about the floristic records. Although further improvements are needed, we discuss how these data can be used for research and policy actions and to develop conservation projects

    Conditional genome engineering reveals canonical and divergent roles for the Hus1 component of the 9-1-1 complex in the maintenance of the plastic genome of Leishmania.

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    Leishmania species are protozoan parasites whose remarkably plastic genome limits the establishment of effective genetic manipulation and leishmaniasis treatment. The strategies used by Leishmania to maintain its genome while allowing variability are not fully understood. Here, we used DiCre-mediated conditional gene deletion to show that HUS1, a component of the 9-1-1 (RAD9- RAD1-HUS1) complex, is essential and is required for a G2/M checkpoint. By analyzing genome wide instability in HUS1 ablated cells, HUS1 is shown to have a conserved role, by which it preserves genome stability, and also a divergent role, by which it promotes genome variability. These roles of HUS1 are related to distinct patterns of formation and resolution of single-stranded DNA and γH2A, throughout the cell cycle. Our findings suggest that Leishmania 9-1-1 subunits have evolved to co-opt canonical genomic maintenance and genomic variation functions. Hence, this study reveals a pivotal function of HUS1 in balancing genome stability and transmission in Leishmania. These findings may be relevant to understanding the evolution of genome maintenance and plasticity in other pathogens and eukaryote

    Notulae to the Italian alien vascular flora: 12

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    In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates published elsewhere are provided as Suppl. material 1

    Notulae to the Italian alien vascular flora: 14

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    In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. materia
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