43 research outputs found

    Novel RNA viruses from the Atlantic Ocean: Ecogenomics, biogeography, and total virioplankton mass contribution from surface to the deep ocean

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    Marine viruses play a major role in the energy and nutrient cycle and affect the evolution of their hosts. Despite their importance, there is still little knowledge about RNA viruses. Here, we have explored the Atlantic Ocean, from surface to deep (4.296 m), and used viromics and quantitative methods to unveil the genomics, biogeography, and the mass contribution of RNA viruses to the total viroplankton. A total of 2481 putative RNA viral contigs (>500 bp) and 107 larger bona fide RNA viral genomes (>2.5 kb) were identified; 88 of them representing novel viruses belonging mostly to two clades: Yangshan assemblage (sister clade to the class Alsuviricetes) and Nodaviridae. These viruses were highly endemic and locally abundant, with little or no presence in other oceans since only ≈15% of them were found in at least one of the Tara sampling metatranscriptomes. Quantitative data indicated that the abundance of RNA viruses in the surface and deep chlorophyll maximum zone was within ≈106 VLP/mL representing a potential contribution of 5.2%–24.4% to the total viroplankton community (DNA and RNA viruses), with DNA viruses being the predominant members (≈107 VLP/mL). However, for the deep sample, the observed trend was the opposite, although as further discussed, several biases should be considered. Together these results contribute to our understanding of the diversity, abundance, and distribution of RNA viruses in the oceans and provide a basis for further investigation into their ecological roles and biogeography.This work was supported by the Generalitat Valenciana ACIF2020 grant and by the research grants funded by Spanish Ministry of Science and Innovation (refs. RTI2018-094248-B-I00 and PID2021-125175OB-I00), and by the Gordon and Moore Foundation (ref. 5334)

    Enhanced therapeutic effect using sequential administration of antigenically distinct oncolytic viruses expressing oncostatin M in a Syrian hamster orthotopic pancreatic cancer model

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    The limited efficacy of current treatments against pancreatic cancer has prompted the search of new alternatives such as virotherapy. Activation of the immune response against cancer cells is emerging as one of the main mechanisms of action of oncolytic viruses (OV). Direct oncolysis releases tumor antigens, and viral replication within the tumor microenvironment is a potent danger signal. Arming OV with immunostimulatory transgenes further enhances their therapeutic effect. However, standard virotherapy protocols do not take full advantage of OV as cancer vaccines because repeated viral administrations may polarize immune responses against strong viral antigens, and the rapid onset of neutralizing antibodies limits the efficacy of redosing. An alternative paradigm based on sequential combination of antigenically distinct OV has been recently proposed

    A comprehensive overview of grain development in Brachypodium distachyon variety Bd21

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    A detailed and comprehensive understanding of seed reserve accumulation is of great importance for agriculture and crop improvement strategies. This work is part of a research programme aimed at using Brachypodium distachyon as a model plant for cereal grain development and filling. The focus was on the Bd21-3 accession, gathering morphological, cytological, and biochemical data, including protein, lipid, sugars, starch, and cell-wall analyses during grain development. This study highlighted the existence of three main developmental phases in Brachypodium caryopsis and provided an extensive description of Brachypodium grain development. In the first phase, namely morphogenesis, the embryo developed rapidly reaching its final morphology about 18 d after fertilization (DAF). Over the same period the endosperm enlarged, finally to occupy 80% of the grain volume. During the maturation phase, carbohydrates were continuously stored, mainly in the endosperm, switching from sucrose to starch accumulation. Large quantities of β-glucans accumulated in the endosperm with local variations in the deposition pattern. Interestingly, new β-glucans were found in Brachypodium compared with other cereals. Proteins (i.e. globulins and prolamins) were found in large quantities from 15 DAF onwards. These proteins were stored in two different sub-cellular structures which are also found in rice, but are unusual for the Pooideae. During the late stage of development, the grain desiccated while the dry matter remained fairly constant. Brachypodium exhibits some significant differences with domesticated cereals. Beta-glucan accumulates during grain development and this cell wall polysaccharide is the main storage carbohydrate at the expense of starch

    Competition is the mechanism of biocontrol of brown rot in stone fruit by Penicillium frequentans

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    The mechanism of biocontrol of brown rot in stone fruit by Penicillium frequentans Westling (Pf909) was investigated using in vitro and in vivo growth assays and a benomyl-resistant strain of Monilinia fructicola (G Winter) Honey (Mf3C). For the in vitro assays, Pf909 and Mf3C conidia were suspended in Czapek-Dox broth, which was amended or not amended with a skin extract of mature peaches. The growth and germination of Pf909 and Mf3C conidia were determined by counting the number of colony-forming units on potato dextrose agar plates, which were amended or not amended with 0.5 g ml−1 benomyl. In some of the assays, germinated Pf909 conidia were used before their exposure to Mf3C conidia. For the in vivo assays, healthy cherries were inoculated with Mf3C conidia before and after applying Pf909 conidia on the cherry surface and the incidence of brown rot was recorded for seven days. Since we found that Pf909 conidia compete with Mf3C conidia for space and nutrients in the different assays, we concluded that competition is the probable primary mechanism of biocontrol of Pf909. © 2017, International Organization for Biological Control (IOBC)

    A Versatile Vector for In Vivo Monitoring of Type I Interferon Induction and Signaling.

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    Development of reporter systems for in vivo examination of IFN-β induction or signaling of type I interferon (IFN-I) pathways is of great interest in order to characterize biological responses to different inducers such as viral infections. Several reporter mice have been developed to monitor the induction of both pathways in response to different agonists. However, alternative strategies that do not require transgenic mice breeding have to date not been reported. In addition, detection of these pathways in vivo in animal species other than mice has not yet been addressed. Herein we describe a simple method based on the use of an adeno-associated viral vector (AAV8-3xIRF-ISRE-Luc) containing an IFN-β induction and signaling-sensitive promoter sequence controlling the expression of the reporter gene luciferase. This vector is valid for monitoring IFN-I responses in vivo elicited by diverse stimuli in different organs. Intravenous administration of the vector in C57BL/6 mice and Syrian hamsters was able to detect activation of the IFN pathway in the liver upon systemic treatment with different pro-inflammatory agents and infection with Newcastle disease virus (NDV). In addition, intranasal instillation of AAV8-3xIRF-ISRE-Luc showed a rapid and transient IFN-I response in the respiratory tract of mice infected with the influenza A/PR8/34 virus lacking the NS1 protein. In comparison, this response was delayed and exacerbated in mice infected with influenza A/PR/8 wild type virus. In conclusion, the AAV8-3xIRF-ISRE-Luc vector offers the possibility of detecting IFN-I activation in response to different stimuli and in different animal models with no need for reporter transgenic animals

    <i>In vivo</i> activity of AAV8-3xIRF-ISRE-Luc in hamster in response to intravenous NDV-F3AA-GFP LaSota administration.

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    <p>Syrian hamsters were inoculated iv with 1x10<sup>11</sup> vg of the AAV8-3xIRF-ISRE-Luc vector. Three weeks later, animals received an iv administration of 1x10<sup>9</sup> iu NDV-F3AA-GFP LaSota. A) <i>In vivo</i> luciferase activity was monitored at 10, 24, 48 and 72 hours after iv administration of the NDV virus. Each line represents an individual hamster. B) Image of a representative hamster before (basal) and 10 hours after the first NDV administration. C) Luciferase activity stimulation in hamsters receiving two doses of NDV-F3AA-GFP LaSota 6 weeks apart one from the other. D) Type I IFN activity in serum of hamsters before and 24 hours after second NDV administration, measured by bio-assay. E) NDV neutralizing antibodies in serum of hamsters before and 6 weeks after the first NDV administration. These data are from one experiment representative of two.</p

    <i>In vivo</i> reporter activity of AAV8-3xIRF-ISRE-Luc in the respiratory tract.

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    <p>Mice received an intranasal instillation of AAV8-3xIRF-ISRE-Luc (1x10<sup>11</sup> viral genomes/mouse) and were then divided in 4 groups, according to the following intranasal stimuli: Saline solution (Mock); 2x107 iu NDV-F3AA-GFP LaSota; 2x10<sup>7</sup> iu influenza A/PR8/34-ΔNS1 or 2x10<sup>2</sup> iu Wt A/PR8/34. A) Luciferase activity was measured by BLI in the upper and lower respiratory tract at the indicated times. B) Representative images of mice before (baseline) and 120 hours after Wt PR8 infection. Each line represents an individual mouse. These data are from one experiment representative of two.</p
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