571 research outputs found

    Insights into the origin of metazoan filopodia and microvilli.

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    Filopodia are fine actin-based cellular projections used for both environmental sensing and cell motility, and they are essential organelles for metazoan cells. In this study, we reconstruct the origin of metazoan filopodia and microvilli. We first report on the evolutionary assembly of the filopodial molecular toolkit and show that homologs of many metazoan filopodial components, including fascin and myosin X, were already present in the unicellular or colonial progenitors of metazoans. Furthermore, we find that the actin crosslinking protein fascin localizes to filopodia-like structures and microvilli in the choanoflagellate Salpingoeca rosetta. In addition, homologs of filopodial genes in the holozoan Capsaspora owczarzaki are upregulated in filopodia-bearing cells relative to those that lack them. Therefore, our findings suggest that proteins essential for metazoan filopodia and microvilli are functionally conserved in unicellular and colonial holozoans and that the last common ancestor of metazoans bore a complex and specific filopodial machinery

    The repertoire of mutational signatures in human cancer

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    Somatic mutations in cancer genomes are caused by multiple mutational processes, each of which generates a characteristic mutational signature(1). Here, as part of the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium(2) of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA), we characterized mutational signatures using 84,729,690 somatic mutations from 4,645 whole-genome and 19,184 exome sequences that encompass most types of cancer. We identified 49 single-base-substitution, 11 doublet-base-substitution, 4 clustered-base-substitution and 17 small insertion-and-deletion signatures. The substantial size of our dataset, compared with previous analyses(3-15), enabled the discovery of new signatures, the separation of overlapping signatures and the decomposition of signatures into components that may represent associated-but distinct-DNA damage, repair and/or replication mechanisms. By estimating the contribution of each signature to the mutational catalogues of individual cancer genomes, we revealed associations of signatures to exogenous or endogenous exposures, as well as to defective DNA-maintenance processes. However, many signatures are of unknown cause. This analysis provides a systematic perspective on the repertoire of mutational processes that contribute to the development of human cancer.Peer reviewe

    LaeA and VeA are involved in growth morphology, asexual development, and mycotoxin production in Alternaria alternata

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    Alternaria alternata is a common filamentous fungus that contaminates various fruits, grains and vegetables causing important economic losses to farmers and the food industry. A. alternata is a mycotoxigenic mould, which may jeopardize human and animal health. Two of the most common A. alternata mycotoxins found in food and feed are alternariol and alternariol monomethyl ether. In this study we examined the role of LaeA and VeA, two regulatory proteins belonging to the velvet family, which have been described to be involved in several functions in many fungi including secondary metabolism. We found that deletion of laeA and veA genes, respectively, greatly reduced sporulation and strongly compromised mycotoxin production, both in vitro or during pathogenesis of tomato fruits. We have also studied how the loss of laeA and veA may affect expression of genes related to alternariol and alternariol monomethyl ether biosynthesis (pksJ and altR), and to melanin biosynthesis (cmrA, pksA).We are also grateful to the Catalonian Government (XaRTA-Reference Network on Food Technology) for their financial support. N. Estiarte thanks the Secretaria de Universitats i Recerca del Departament d'Economia i Coneixement of the Generalitat de Catalunya for the pre-doctoral grant (FI-DGR 2013)

    Acclimatised rumen culture for raw microalgae conversion into biogas: Linking microbial community structure and operational parameters in anaerobic membrane bioreactors (AnMBR)

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    [EN] Ruminal fluid was inoculated in an Anaerobic Membrane Reactor (AnMBR) to produce biogas from raw Scenedesmus. This work explores the microbial ecology of the system during stable operation at different solids retention times (SRT). The 16S rRNA amplicon analysis revealed that the acclimatised community was mainly composed of Anaerolineaceae, Spirochaetaceae, Lentimicrobiaceae and Cloacimonetes fermentative and hydrolytic members. During the highest biodegradability achieved in the AnMBR (62%) the dominant microorganisms were Fervidobacterium and Methanosaeta. Different microbial community clusters were observed at different SRT conditions. Interestingly, syntrophic bacteria Gelria and Smithella were enhanced after increasing 2-fold the organic loading rate, suggesting their importance in continuous systems producing biogas from raw microalgae.This research work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO, Projects CTM2011-28595-C02-01 and CTM2011-28595-C02-02), which is gratefully acknowledged. The Education, Investigation, Culture and sports Council from the Valencian Generality for the Post-Doctoral fellowship of the third co-author is also acknowledged (APOSTD/2016/104). The authors are thankful to Ion Pérez Baena from the Universitat Politècnica de Valencia, Institut de Ciència I Tecnología Animal for gently providing the ruminal fluid use in this work.Zamorano-López, N.; Borrás Falomir, L.; Giménez, JB.; Seco Torrecillas, A.; Aguado García, D. (2019). Acclimatised rumen culture for raw microalgae conversion into biogas: Linking microbial community structure and operational parameters in anaerobic membrane bioreactors (AnMBR). Bioresource Technology. 290:1-9. https://doi.org/10.1016/j.biortech.2019.121787S1929
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