299 research outputs found

    The genome of the Pacific oyster Crassostrea gigas brings new insights on the massive expansion of the C1q gene family in Bivalvia

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    C1q domain-containing (C1qDC) proteins are regarded as important players in the innate immunity of bivalve mollusks and other invertebrates and their highly adaptive binding properties indicate them as efficient pathogen recognition molecules. Although experimental studies support this view, the molecular data available at the present time are not sufficient to fully explain the great molecular diversification of this family, present in bivalves with hundreds of C1q coding genes. Taking advantage of the fully sequenced genome of the Pacific oyster Crassostrea gigas and more than 100 transcriptomic datasets, we: (i) re-annotated the oyster C1qDC loci, thus identifying the correct genomic organization of 337 C1qDC genes, (ii) explored the expression pattern of oyster C1qDC genes in diverse developmental stages and adult tissues of unchallenged and experimentally treated animals; (iii) investigated the expansion of the C1qDC gene family in all major bivalve subclasses.Overall, we provide a broad description of the functionally relevant features of oyster C1qDC genes, their comparative expression levels and new evidence confirming that a gene family expansion event has occurred during the course of Bivalve evolution, leading to the diversification of hundreds of different C1qDC genes in both the Pteriomorphia and Heterodonta subclasses

    Extensive Tandem Duplication Events Drive the Expansion of the C1q-Domain-Containing Gene Family in Bivalves

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    C1q-domain-containing (C1qDC) proteins are rapidly emerging as key players in the innate immune response of bivalve mollusks. Growing experimental evidence suggests that these highly abundant secretory proteins are involved in the recognition of microbe-associated molecular patterns, serving as lectin-like molecules in the bivalve proto-complement system. While a large amount of functional data concerning the binding specificity of the globular head C1q domain and on the regulation of these molecules in response to infection are quickly accumulating, the genetic mechanisms that have led to the extraordinary lineage-specific expansion of the C1qDC gene family in bivalves are still largely unknown. The analysis of the chromosome-scale genome assembly of the Eastern oyster Crassostrea virginica revealed that the 476 oyster C1qDC genes, far from being uniformly distributed along the genome, are located in large clusters of tandemly duplicated paralogs, mostly found on chromosomes 7 and 8. Our observations point out that the evolutionary process behind the development of a large arsenal of C1qDC lectin-like molecules in marine bivalves is still ongoing and likely based on an unequal crossing over

    GUARDARE IL MONDO CON I NEUTRINI: IL SOLE, LA TERRA E L'UNIVERSO

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    Neutrinos are the most elusive and ubiquitous known building blocks in the Universe. Predicted by Wolfgang Pauli in 1930 and then theoretically elaborated by Enrico Fermi and Ettore Majorana in the following years, they were discovered experimentally in 1956 and since then they have never ceased to surprise us with their, sometimes disconcerting, properties. There are three different types that can transform into each other, devoid of electric charge, very light but with a very small mass, at least a million times lower than that of the electron. Although we know that they have a mass, we still do not know how much they weigh. In nature they are abundantly emitted by the Sun and stars, from the nucleus of the most active galaxies and from our planet they were produced in such abundance in the first moments of the Big Bang to the point of permeating the entire Universe with neutrinos. They are also produced in large numbers by nuclear reactors and particle accelerators, which allow us accurate and controlled studies. The neutrinos emitted by natural sources are unique messengers about the sources themselves and about the physical mechanisms that generate them. This note summarizes the main steps in the history of neutrinos, their most conspicuous properties and above all how much it has been possible to learn about the stars, the Earth, and the Sun thanks to them. Particular attention will be given to the recent results at the Gran Sasso National Laboratories obtained from the Borexino experiment which, by means of neutrinos, completed for the first time in 2020 the study of all nuclear fusion reactions that take place in the Sun, including that, minority but very important, catalyzed by the presence of Carbon, Nitrogen and Oxygen in the Sun's core

    Molecular Diversity of Mytilin-Like Defense Peptides in Mytilidae (Mollusca, Bivalvia)

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    The CS-\u3b1\u3b2 architecture is a structural scaffold shared by a high number of small, cationic, cysteine-rich defense peptides, found in nearly all the major branches of the tree of life. Although several CS-\u3b1\u3b2 peptides involved in innate immune response have been described so far in bivalve mollusks, a clear-cut definition of their molecular diversity is still lacking, leaving the evolutionary relationship among defensins, mytilins, myticins and other structurally similar antimicrobial peptides still unclear. In this study, we performed a comprehensive bioinformatic screening of the genomes and transcriptomes available for marine mussels (Mytilida), redefining the distribution of mytilin-like CS-\u3b1\u3b2 peptides, which in spite of limited primary sequence similarity maintain in all cases a well-conserved backbone, stabilized by four disulfide bonds. Variations in the size of the alpha-helix and the two antiparallel beta strand region, as well as the positioning of the cysteine residues involved in the formation of the C1\u2013C5 disulfide bond might allow a certain degree of structural flexibility, whose functional implications remain to be investigated. The identification of mytilins in Trichomya and Perna spp. revealed that many additional CS-\u3b1\u3b2 AMPs remain to be formally described and functionally characterized in Mytilidae, and suggest that a more robust scheme should be used for the future classification of such peptides with respect with their evolutionary origi

    IL-17 signaling components in bivalves: Comparative sequence analysis and involvement in the immune responses

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    The recent discovery of soluble immune-regulatory molecules in invertebrates takes advantage of the rapid growth of next generation sequencing datasets. Following protein domain searches in the transcriptomes of 31 bivalve spp. and in few available mollusk genomes, we retrieved 59 domains uniquely identifying interleukin 17 (IL-17) and 96 SEFIR domains typical of IL-17 receptors and CIKS/ACT1 proteins acting downstream in the IL-17 signaling pathway. Compared to the Chordata IL-17 family members, we confirm a separate clustering of the bivalve domain sequences and a consistent conservation pattern of amino acid residues. Analysis performed at transcript and genome level allowed us to propose an updated view of the components outlining the IL-17 signaling pathway in Mytilus galloprovincialis and Crassostrea gigas (in both species, homology modeling reduced the variety of IL-17 domains to only two 3D structures). Digital expression analysis indicated more heterogeneous expression levels for the mussel and oyster IL-17 ligands than for IL-17 receptors and CIKS/CIKSL proteins. Besides, new qPCR analyses confirmed such gene expression trends in hemocytes and gills of mussels challenged with heat-killed bacteria. These results uphold the involvement of an ancient IL-17 signaling pathway in the bivalve immune responses and, likewise in humans, suggest the possibility of distinctive modulatory roles of individual IL-17s/IL-17 receptors. Overall, the common evidence of pro-inflammatory cytokines and inter-related intracellular signaling pathways in bivalves definitely adds complexity to the invertebrate immunity

    A selective alpha1D-adrenoreceptor antagonist inhibits human prostate cancer cell proliferation and motility "in vitro"

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    The progression of prostate cancer (PC) to a metastatic hormone refractory disease is the major contributor to the overall cancer mortality in men, mainly because the conventional therapies are generally ineffective at this stage. Thus, other therapeutic options are needed as alternatives or in addition to the classic approaches to prevent or delay tumor progression. Catecholamines participate to the control of prostate cell functions by the activation of alpha1-adrenoreceptors (alpha1-AR) and increased sympathetic activity has been linked to PC development and evolution. Molecular and pharmacological studies identified three alpha1-AR subtypes (A, B and D), which differ in tissue distribution, cell signaling, pharmacology and physiological role. Within the prostate, alpha1A-ARs mainly control stromal cell functions, while alpha1B- and alpha1D- subtypes seem to modulate glandular epithelial cell growth. The possible direct contribution of alpha1D-ARs in tumor biology is supported by their overexpression in PC. The studies here presented investigate the "in vitro" antitumor action of A175, a selective alpha1D-AR antagonist we have recently obtained by modifying the potent, but not subtype-selective alpha1-AR antagonist (S)-WB4101, in the hormone-refractory PC3 and DU145 PC cell lines. The results indicate that A175 has an alpha1D-AR-mediated significant and dose-dependent antiproliferative action that possibly involves the induction of G0/G1 cell cycle arrest, but not apoptosis. In addition, A175 reduces cell migration and adhesiveness to culture plates. In conclusion, our work clarified some cellular aspects promoted by alpha1D-AR activity modulation and supports a further pharmacological approach in the cure of hormone-refractory PC, by targeting specifically this AR subtype
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