Sequence determination of a satellite RNA isolated from Aspergillus foetidus

Aspergillus foetidus virus (AfV) has at least two distinct particle types, designated as AfV-fast (F) and AfV-slow (S). AfV-S includes AfV-S1, a victorivirus; AfV-S2, an unclassified satellite RNA; and AfV-S3, a previously uncharacterized dsRNA element. Here, we describe the complete sequence of AfV-S3, which is a short non-coding RNA with no known homologs. AfV-S3 is predicted to form an extended secondary structure, shares a 5’ terminus with AfV-S2, and is a satellite RNA possibly dependent on both AfV-S1 and AfV-S2. This work concludes the sequencing of the A. foetidus viromePeer reviewe

Identification and sequence determination of a novel double-stranded RNA mycovirus from the entopathogenic fungus Beauveria bassina

The final publication is available at Springer via https://doi.org/10.1007/s00705-014-2332-8.An isolate of the entomopathogenic fungus Beauveria bassiana was found to contain five double-stranded (ds) RNA elements ranging from 1.5 to more than 3 kbp. The complete sequence of the largest dsRNA element is described here. Analysis of the RdRp nucleotide sequence reveals its similarity to unclassified dsRNA elements, such as Alternaria longipes dsRNA virus 1, and its distant relationship to the RNA-dependent RNA polymerases of members of the family PartitiviridaePeer reviewedFinal Accepted Versio

Aspergillus fumigatus mycovirus causes mild hypervirulent effect on pathogenicity when tested on Galleria mellonella

This document is the Accepted Manuscript version of the following article: Selin Ozkan, and Robert H. A. Coutts, 'Aspergillus fumigatus mycovirus causes mild hypervirulent effect on pathogenicity when tested on Galleria mellonella', Fungal Genetics and Biology, Vol. 76: 20-26, March 2015, doi: https://doi.org/10.1016/j.fgb.2015.01.003. This manuscript version is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).Mycoviruses are a specific group of viruses that naturally infect and replicate in fungi. The importance of mycoviruses was revealed after their effects were identified not only in economically important fungi but also in the human pathogenic fungus Aspergillus fumigatus. The latter was shown recently to harbor at least three different types of mycoviruses including a chrysovirus, a partitivirus and an as yet uncharacterized virus. Assessment of virulence in the presence and absence of mycoviruses in A. fumigatus is pivotal to understanding its pathogenicity. Here, we have investigated, for the first time, the effects of mycoviruses on the pathogenicity of A. fumigatus as assessed using larvae of the greater wax moth Galleria mellonella. In order to observe the effects of mycoviruses on pathogenicity, G. mellonella were injected with virus-free and virus-infected isolates of A. fumigatus and post-infection survival times were analyzed along with the fungal burden. Neither chrysovirus nor partitivirus infection affected fungal pathogenicity when survival rates were assessed which, for the chrysovirus, agreed with a previous study on murine pathogenicity. However statistically significant differences were observed in survival rates and fungal burden in the presence of the uncharacterized A78 virus. Here we show, for the first time, the effects of a partitivirus and an uncharacterized A78 virus on the pathogenicity of A. fumigatusPeer reviewedFinal Accepted Versio

Mycovirus Containing <em>Aspergillus flavus</em> and Acute Lymphoblastic Leukemia: Carcinogenesis beyond Mycotoxin Production

Carcinogenic effects of Aspergillus spp. have been well established and generally attributed to a variety of mycotoxin productions, particularly aflatoxins. It is known that most carcinogenic mycotoxins, with the exception of fumonisins, are genotoxic and mutagenic, causing chromosomal aberrations, micronuclei, DNA single-strand breaks, sister chromatid exchange, unscheduled DNA synthesis etc. Some Aspergillus spp. are infected with mycoviruses which can result in loss of aflatoxin production. The effects of mycovirus containing Aspergillus on human health have not been fully evaluated. Recent studies in patients with acute lymphoblastic leukemia, in full remission, have revealed the existence of antibody to the products of a certain Aspergillus flavus isolate which harbored an unknown mycovirus. Exposure of blood mononuclear cells from these patients, but not controls, to the products of this organism had reproduced cell surface phenotypes and genetic markers, characteristic of acute lymphoblastic leukemia. Carcinogenic effects of Aspergillus spp. may not always be mycotoxin related and this requires further investigation

Mycoviral Population Dynamics in Spanish Isolates of the Entomopathogenic Fungus Beauveria bassiana

The use of mycoviruses to manipulate the virulence of entomopathogenic fungi employed as biocontrol agents may lead to the development of novel methods to control attacks by insect pests. Such approaches are urgently required, as existing agrochemicals are being withdrawn from the market due to environmental and health concerns. The aim of this work is to investigate the presence and diversity of mycoviruses in large panels of entomopathogenic fungi, mostly from Spain and Denmark. In total, 151 isolates belonging to the genera Beauveria, Metarhizium, Lecanicillium, Purpureocillium, Isaria, and Paecilomyces were screened for the presence of dsRNA elements and 12 Spanish B. bassiana isolates were found to harbor mycoviruses. All identified mycoviruses belong to three previously characterised species, the officially recognised Beauveria bassiana victorivirus 1 (BbVV-1) and the proposed Beauveria bassiana partitivirus 2 (BbPV-2) and Beauveria bassiana polymycovirus 1 (BbPmV-1); individual B. bassiana isolates may harbor up to three of these mycoviruses. Notably, these mycovirus species are under distinct selection pressures, while recombination of viral genomes increases population diversity. Phylogenetic analysis of the RNA-dependent RNA polymerase gene sequences revealed that the current population structure in Spain is potentially a result of both vertical and horizontal mycovirus transmission. Finally, pathogenicity experiments using the Mediterranean fruit fly Ceratitis capitata showed no direct correlation between the presence of any particular mycovirus and the virulence of the B. bassiana isolates, but illustrated potentially interesting isolates that exhibit relatively high virulence, which will be used in more detailed virulence experimentation in the futur

Molecular and biological characterization of a novel partitivirus from Talaromyces pinophilus

© 2024 The Author(s). Published by Elsevier B.V. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Talaromyces spp. have a worldwide distribution, are ecologically diverse and have been isolated from numerous different substrates. Talaromyces spp. are considered biotechnologically important due to their ability to produce a range of enzymes and pigments. Talaromyces pinophilus, belonging to genus Talaromyces and family Trichocomaceae, is known for producing several important bioactive metabolites. Here we report the isolation and characterisation of a partitivirus from T. pinophilus which we have nominated Talaromyces pinophilus partitivirus-1 (TpPV-1). TpPV-1 possesses a genome consisting of three double stranded (ds) RNA segments i.e., dsRNAs1-3, 1824 bp, 1638 bp and 1451 bp respectively, which are encapsidated in icosahedral particles 35 nm in diameter. Both dsRNA1 and dsRNA2 contain a single open reading frame (ORF) encoding respectively a 572 amino acid (aa) protein of 65 kDa and a 504 aa protein of 50 kDa. The third segment (dsRNA3) is potentially a satellite RNA. Phylogenetic analysis revealed that the TpPV-1 belongs to the family Partitiviridae in the proposed genus Zetapartitivirus. TpPV-1 infection decreases the mycelial growth rate of the host fungus and alters pigmentation as indicated by time course experiments performed on a range of different solid media comparing virus-infected and virus-free isogenic lines. This is the first report of mycovirus infection in T. pinophilus and may provide insights into understanding the effect of the mycovirus on the production of enzymes and pigments by the host fungus.Peer reviewe

Current evidence and future perspectives on HuR and breast cancer development, prognosis, and treatment.

This is the Accepted Manuscript version of the following article, "Ioly Kotta-Loizou, et al., “Current Evidence and Future Perspectives on HuR and Breast Cancer Development, Prognosis, and Treatment”, Neoplasia, Vol. 18(11): 674-688, October 2016." The final published version is available at:https://doi.org/10.1016/j.neo.2016.09.002 Copyright © 2016, Elsevier.Hu-antigen R (HuR) is an RNA-binding posttranscriptional regulator that belongs to the Hu/ELAV family. HuR expression levels are modulated by a variety of proteins, microRNAs, chemical compounds, or the microenvironment, and in turn, HuR affects mRNA stability and translation of various genes implicated in breast cancer formation, progression, metastasis, and treatment. The aim of the present review is to critically summarize the role of HuR in breast cancer development and its potential as a prognosticator and a therapeutic target. In this aspect, all the existing English literature concerning HuR expression and function in breast cancer cell lines, in vivo animal models, and clinical studies is critically presented and summarized. HuR modulates many genes implicated in biological processes crucial for breast cancer formation, growth, and metastasis, whereas the link between HuR and these processes has been demonstrated directly in vitro and in vivo. Additionally, clinical studies reveal that HuR is associated with more aggressive forms of breast cancer and is a putative prognosticator for patients' survival. All the above indicate HuR as a promising drug target for cancer therapy; nevertheless, additional studies are required to fully understand its potential and determine against which types of breast cancer and at which stage of the disease a therapeutic agent targeting HuR would be more effective.Peer reviewedFinal Accepted Versio

Suppression of virus induced local lesions in plasmolysed leaf tissue

It has been demonstrated previously that protoplasts derived from leaves which normally respond in vivo to virus inoculation, with the formation of necrotic local lesions show no such response when inoculated in vitro [1]. In this study mesophyll cells, isolated from one another by plasmolysis of whole leaves, after infection were investigated. When primary leaves of cowpea (Vigna sinensis Endl. var. Blackeye) were floated on the non-permeating, non-metabolizable carbohydrate mannitol, at plasmolysing concentration (0.5 M), immediately, or at any time up to 24 h after inoculation with tobacco necrosis virus (TNV R/1 : 1.5/19 : S/S : S/Fu, [2]), complete suppression of normal local lesion symptoms was observed. Concurrent with this suppression was a decrease in virus content, as determined by local lesion estimates of viral RNA, and nucleoprotein. Infected leaves only produced lesions if deplasmolysed immediately after initial plasmolysis. Floating TNV infected leaves on a series of mannitol solutions from 0 to 0.5 M, showed a progressive decrease in lesion diameter, and these leaves contained the expected infectious levels of viral RNA and nucleoprotein, with significantly more RNA and whole virus in 0.2 M mannitol treated leaves and significantly less in 0.4 and 0.5 M samples. The implications of these results with regard to necrogenesis in virus-infected, hypersensitively reacting plants are discussedPeer reviewe

First report of an Endornavirus in the Cucurbitaceae

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Pseudorecombination and complementation between potato yellow mosaic geminivirus and tomato golden mosaic geminivirus

Pseudorecombinants made by exchanging the cloned, infectious genome components (DNAs A and B) of potato yellow mosaic geminivirus (PYMV) and the common strain (cs) of tomato golden mosaic geminivirus (csTGMV) are not infectious in their common host Nicotiana benthamiana. In an N. benthamiana leaf disc assay neither PYMV DNA A nor TGMV DNA A trans-replicated each other's DNA B component. The ability of TGMV to mediate the systemic movement of each other's DNA A was investigated following co-inoculation of N. benthamiana with both genome components of one virus (the helper virus) and DNA A of the other virus (the dependent virus). Movement of the dependent virus DNA A in both cases illustrates interchangeability between the DNA B-encoded movement proteins of New World geminiviruses which infect solanaceous hosts. We have studied this genetic interchangeability further in separate co-agroinoculation experiments with N. benthamiana plants using TGMV DNA A to complement mutations in PYMV open reading frame (ORF) AC2, which encodes a protein that trans-activates the expression of virion sense promoters, and in PYMV ORF AC3, which specfies a protein that enhances viral DNA replication. TGMV DNA A complemented a PYMV AC2 mutant and restored its infectivity and it also complemented a PYMV AC3 mutant and restored the reduced DNA phenotype.Peer reviewe