Next Issue
Previous Issue

E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Table of Contents

Viruses, Volume 7, Issue 2 (February 2015) , Pages 456-856

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
View options order results:
result details:
Displaying articles 1-22
Export citation of selected articles as:
Open AccessShort Communication
Complete Genome Analysis of a Rabbit Rotavirus Causing Gastroenteritis in a Human Infant
Viruses 2015, 7(2), 844-856; https://doi.org/10.3390/v7020844
Received: 20 January 2015 / Revised: 10 February 2015 / Accepted: 13 February 2015 / Published: 17 February 2015
Cited by 9 | Viewed by 2701 | PDF Full-text (787 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Group A rotaviruses (RVA) are responsible for causing infantile diarrhea both in humans and animals. The molecular characteristics of lapine RVA strains are only studied to a limited extent and so far G3P[14] and G3P[22] were found to be the most common G/P-genotypes. [...] Read more.
Group A rotaviruses (RVA) are responsible for causing infantile diarrhea both in humans and animals. The molecular characteristics of lapine RVA strains are only studied to a limited extent and so far G3P[14] and G3P[22] were found to be the most common G/P-genotypes. During the 2012-2013 rotavirus season in Belgium, a G3P[14] RVA strain was isolated from stool collected from a two-year-old boy. We investigated whether RVA/Human-wt/BEL/BE5028/2012/G3P[14] is completely of lapine origin or the result of reassortment event(s). Phylogenetic analyses of all gene segments revealed the following genotype constellation: G3-P[14]-I2-R2-C2-M3-A9-N2-T6-E5-H3 and indicated that BE5028 probably represents a rabbit to human interspecies transmission able to cause disease in a human child. Interestingly, BE5028 showed a close evolutionary relationship to RVA/Human-wt/BEL/B4106/2000/G3P[14], another lapine-like strain isolated in a Belgian child in 2000. The phylogenetic analysis of the NSP3 segment suggests the introduction of a bovine(-like) NSP3 into the lapine RVA population in the past 12 years. Sequence analysis of NSP5 revealed a head-to-tail partial duplication, combined with two short insertions and a deletion, indicative of the continuous circulation of this RVA lineage within the rabbit population. Full article
Figures

Figure 1

Open AccessReview
The Role of RNA Interference (RNAi) in Arbovirus-Vector Interactions
Viruses 2015, 7(2), 820-843; https://doi.org/10.3390/v7020820
Received: 11 September 2014 / Revised: 10 December 2014 / Accepted: 4 February 2015 / Published: 17 February 2015
Cited by 54 | Viewed by 3888 | PDF Full-text (357 KB) | HTML Full-text | XML Full-text
Abstract
RNA interference (RNAi) was shown over 18 years ago to be a mechanism by which arbovirus replication and transmission could be controlled in arthropod vectors. During the intervening period, research on RNAi has defined many of the components and mechanisms of this antiviral [...] Read more.
RNA interference (RNAi) was shown over 18 years ago to be a mechanism by which arbovirus replication and transmission could be controlled in arthropod vectors. During the intervening period, research on RNAi has defined many of the components and mechanisms of this antiviral pathway in arthropods, yet a number of unexplored questions remain. RNAi refers to RNA-mediated regulation of gene expression. Originally, the term described silencing of endogenous genes by introduction of exogenous double-stranded (ds)RNA with the same sequence as the gene to be silenced. Further research has shown that RNAi comprises three gene regulation pathways that are mediated by small RNAs: the small interfering (si)RNA, micro (mi)RNA, and Piwi-interacting (pi)RNA pathways. The exogenous (exo-)siRNA pathway is now recognized as a major antiviral innate immune response of arthropods. More recent studies suggest that the piRNA and miRNA pathways might also have important roles in arbovirus-vector interactions. This review will focus on current knowledge of the role of the exo-siRNA pathway as an arthropod vector antiviral response and on emerging research into vector piRNA and miRNA pathway modulation of arbovirus-vector interactions. Although it is assumed that arboviruses must evade the vector’s antiviral RNAi response in order to maintain their natural transmission cycles, the strategies by which this is accomplished are not well defined. RNAi is also an important tool for arthropod gene knock-down in functional genomics studies and in development of arbovirus-resistant mosquito populations. Possible arbovirus strategies for evasion of RNAi and applications of RNAi in functional genomics analysis and arbovirus transmission control will also be reviewed. Full article
(This article belongs to the Special Issue Interactions between Arboviruses and Arthropod Vectors)
Open AccessArticle
Intranasal Administration of Maleic Anhydride-Modified Human Serum Albumin for Pre-Exposure Prophylaxis of Respiratory Syncytial Virus Infection
Viruses 2015, 7(2), 798-819; https://doi.org/10.3390/v7020798
Received: 16 October 2014 / Revised: 5 February 2015 / Accepted: 10 February 2015 / Published: 16 February 2015
Cited by 6 | Viewed by 2767 | PDF Full-text (1382 KB) | HTML Full-text | XML Full-text
Abstract
Respiratory syncytial virus (RSV) is the leading cause of pediatric viral respiratory tract infections. Neither vaccine nor effective antiviral therapy is available to prevent and treat RSV infection. Palivizumab, a humanized monoclonal antibody, is the only product approved to prevent serious RSV infection, [...] Read more.
Respiratory syncytial virus (RSV) is the leading cause of pediatric viral respiratory tract infections. Neither vaccine nor effective antiviral therapy is available to prevent and treat RSV infection. Palivizumab, a humanized monoclonal antibody, is the only product approved to prevent serious RSV infection, but its high cost is prohibitive in low-income countries. Here, we aimed to identify an effective, safe, and affordable antiviral agent for pre-exposure prophylaxis (PrEP) of RSV infection in children at high risk. We found that maleic anhydride (ML)-modified human serum albumin (HSA), designated ML-HSA, exhibited potent antiviral activity against RSV and that the percentages of the modified lysines and arginies in ML- are correlated with such anti-RSV activity. ML-HSA inhibited RSV entry and replication by interacting with viral G protein and blocking RSV attachment to the target cells, while ML-HAS neither bound to F protein, nor inhibited F protein-mediated membrane fusion. Intranasal administration of ML-HSA before RSV infection resulted in significant decrease of the viral titers in the lungs of mice. ML-HSA shows promise for further development into an effective, safe, affordable, and easy-to-use intranasal regimen for pre-exposure prophylaxis of RSV infection in children at high risk in both low- and high-income countries. Full article
Figures

Figure 1

Open AccessArticle
Bioinformatics Tools for Small Genomes, Such as Hepatitis B Virus
Viruses 2015, 7(2), 781-797; https://doi.org/10.3390/v7020781
Received: 11 November 2014 / Revised: 18 December 2014 / Accepted: 10 February 2015 / Published: 16 February 2015
Cited by 11 | Viewed by 3209 | PDF Full-text (393 KB) | HTML Full-text | XML Full-text
Abstract
DNA sequence analysis is undertaken in many biological research laboratories. The workflow consists of several steps involving the bioinformatic processing of biological data. We have developed a suite of web-based online bioinformatic tools to assist with processing, analysis and curation of DNA sequence [...] Read more.
DNA sequence analysis is undertaken in many biological research laboratories. The workflow consists of several steps involving the bioinformatic processing of biological data. We have developed a suite of web-based online bioinformatic tools to assist with processing, analysis and curation of DNA sequence data. Most of these tools are genome-agnostic, with two tools specifically designed for hepatitis B virus sequence data. Tools in the suite are able to process sequence data from Sanger sequencing, ultra-deep amplicon resequencing (pyrosequencing) and chromatograph (trace files), as appropriate. The tools are available online at no cost and are aimed at researchers without specialist technical computer knowledge.
The tools can be accessed at http://hvdr.bioinf.wits.ac.za/SmallGenomeTools, and the source code is available online at https://github.com/DrTrevorBell/SmallGenomeTools. Full article
(This article belongs to the Special Issue Bioinformatics and Computational Biology of Viruses)
Figures

Figure 1

Open AccessReview
Aptamers in Diagnostics and Treatment of Viral Infections
Viruses 2015, 7(2), 751-780; https://doi.org/10.3390/v7020751
Received: 27 November 2014 / Revised: 13 January 2015 / Accepted: 12 February 2015 / Published: 16 February 2015
Cited by 32 | Viewed by 4090 | PDF Full-text (1078 KB) | HTML Full-text | XML Full-text
Abstract
Aptamers are in vitro selected DNA or RNA molecules that are capable of binding a wide range of nucleic and non-nucleic acid molecules with high affinity and specificity. They have been conducted through the process known as SELEX (Systematic Evolution of Ligands by [...] Read more.
Aptamers are in vitro selected DNA or RNA molecules that are capable of binding a wide range of nucleic and non-nucleic acid molecules with high affinity and specificity. They have been conducted through the process known as SELEX (Systematic Evolution of Ligands by Exponential Enrichment). It serves to reach specificity and considerable affinity to target molecules, including those of viral origin, both proteins and nucleic acids. Properties of aptamers allow detecting virus infected cells or viruses themselves and make them competitive to monoclonal antibodies. Specific aptamers can be used to interfere in each stage of the viral replication cycle and also inhibit its penetration into cells. Many current studies have reported possible application of aptamers as a treatment or diagnostic tool in viral infections, e.g., HIV (Human Immunodeficiency Virus), HBV (Hepatitis B Virus), HCV (Hepatitis C Virus), SARS (Severe Acute Respiratory Syndrome), H5N1 avian influenza and recently spread Ebola. This review presents current developments of using aptamers in the diagnostics and treatment of viral diseases. Full article
(This article belongs to the Section Antivirals & Vaccines)
Figures

Figure 1

Open AccessReview
eIF4E as a Control Target for Viruses
Viruses 2015, 7(2), 739-750; https://doi.org/10.3390/v7020739
Received: 12 December 2014 / Revised: 6 February 2015 / Accepted: 11 February 2015 / Published: 16 February 2015
Cited by 11 | Viewed by 3186 | PDF Full-text (794 KB) | HTML Full-text | XML Full-text
Abstract
Translation is a complex process involving diverse cellular proteins, including the translation initiation factor eIF4E, which has been shown to be a protein that is a point for translational regulation. Viruses require components from the host cell to complete their replication cycles. Various [...] Read more.
Translation is a complex process involving diverse cellular proteins, including the translation initiation factor eIF4E, which has been shown to be a protein that is a point for translational regulation. Viruses require components from the host cell to complete their replication cycles. Various studies show how eIF4E and its regulatory cellular proteins are manipulated during viral infections. Interestingly, viral action mechanisms in eIF4E are diverse and have an impact not only on viral protein synthesis, but also on other aspects that are important for the replication cycle, such as the proliferation of infected cells and stimulation of viral reactivation. This review shows how some viruses use eIF4E and its regulatory proteins for their own benefit in order to spread themselves. Full article
Figures

Figure 1

Open AccessReview
Poxviral Ankyrin Proteins
Viruses 2015, 7(2), 709-738; https://doi.org/10.3390/v7020709
Received: 31 December 2014 / Revised: 5 February 2015 / Accepted: 9 February 2015 / Published: 16 February 2015
Cited by 16 | Viewed by 2708 | PDF Full-text (1477 KB) | HTML Full-text | XML Full-text
Abstract
Multiple repeats of the ankyrin motif (ANK) are ubiquitous throughout the kingdoms of life but are absent from most viruses. The main exception to this is the poxvirus family, and specifically the chordopoxviruses, with ANK repeat proteins present in all but three species [...] Read more.
Multiple repeats of the ankyrin motif (ANK) are ubiquitous throughout the kingdoms of life but are absent from most viruses. The main exception to this is the poxvirus family, and specifically the chordopoxviruses, with ANK repeat proteins present in all but three species from separate genera. The poxviral ANK repeat proteins belong to distinct orthologue groups spread over different species, and align well with the phylogeny of their genera. This distribution throughout the chordopoxviruses indicates these proteins were present in an ancestral vertebrate poxvirus, and have since undergone numerous duplication events. Most poxviral ANK repeat proteins contain an unusual topology of multiple ANK motifs starting at the N-terminus with a C-terminal poxviral homologue of the cellular F-box enabling interaction with the cellular SCF ubiquitin ligase complex. The subtle variations between ANK repeat proteins of individual poxviruses suggest an array of different substrates may be bound by these protein-protein interaction domains and, via the F-box, potentially directed to cellular ubiquitination pathways and possible degradation. Known interaction partners of several of these proteins indicate that the NF-κB coordinated anti-viral response is a key target, whilst some poxviral ANK repeat domains also have an F-box independent affect on viral host-range. Full article
(This article belongs to the Special Issue Poxvirus Evolution)
Figures

Figure 1

Open AccessEditorial
Announcing the 2015 Viruses Young Investigator Prize and Graduate Student/Postdoctoral Fellow Travel Awards
Viruses 2015, 7(2), 707-708; https://doi.org/10.3390/v7020707
Received: 5 February 2015 / Accepted: 5 February 2015 / Published: 12 February 2015
Viewed by 2740 | PDF Full-text (403 KB) | HTML Full-text | XML Full-text
Abstract
With the goal of recognizing outstanding contributions to the field of virology by early-career investigators, last year Viruses accepted nominations for a 2015 Young Investigator Prize in Virology. The target age was set at 40 and under. Over 50 nominations were received and [...] Read more.
With the goal of recognizing outstanding contributions to the field of virology by early-career investigators, last year Viruses accepted nominations for a 2015 Young Investigator Prize in Virology. The target age was set at 40 and under. Over 50 nominations were received and were evaluated by a panel of judges comprised of Viruses editorial board members.[...] Full article
(This article belongs to the Section Editorial)
Open AccessEditorial
Morbillivirus Infections: An Introduction
Viruses 2015, 7(2), 699-706; https://doi.org/10.3390/v7020699
Received: 3 February 2015 / Accepted: 5 February 2015 / Published: 12 February 2015
Cited by 17 | Viewed by 3584 | PDF Full-text (423 KB) | HTML Full-text | XML Full-text
Abstract
Research on morbillivirus infections has led to exciting developments in recent years. Global measles vaccination coverage has increased, resulting in a significant reduction in measles mortality. In 2011 rinderpest virus was declared globally eradicated – only the second virus to be eradicated by [...] Read more.
Research on morbillivirus infections has led to exciting developments in recent years. Global measles vaccination coverage has increased, resulting in a significant reduction in measles mortality. In 2011 rinderpest virus was declared globally eradicated – only the second virus to be eradicated by targeted vaccination. Identification of new cellular receptors and implementation of recombinant viruses expressing fluorescent proteins in a range of model systems have provided fundamental new insights into the pathogenesis of morbilliviruses, and their interactions with the host immune system. Nevertheless, both new and well-studied morbilliviruses are associated with significant disease in wildlife and domestic animals. This illustrates the need for robust surveillance and a strategic focus on barriers that restrict cross-species transmission. Recent and ongoing measles outbreaks also demonstrate that maintenance of high vaccination coverage for these highly infectious agents is critical. This introduction briefly summarizes the most important current research topics in this field. Full article
(This article belongs to the Special Issue Morbillivirus Infections)
Figures

Figure 1

Open AccessArticle
Host Recovery and Reduced Virus Level in the Upper Leaves after Potato virus Y Infection Occur in Tobacco and Tomato but not in Potato Plants
Viruses 2015, 7(2), 680-698; https://doi.org/10.3390/v7020680
Received: 10 November 2014 / Accepted: 2 February 2015 / Published: 11 February 2015
Cited by 6 | Viewed by 3045 | PDF Full-text (1245 KB) | HTML Full-text | XML Full-text
Abstract
In this study, the recovery phenomenon following infection with Potato virus Y (PVY) was investigated in tobacco (Nicotiana tobaccum), tomato (Solanum lycopersicum) and potato (Solanum tuberosum) plants. In tobacco plants, infection of severe strains of PVY (PVY [...] Read more.
In this study, the recovery phenomenon following infection with Potato virus Y (PVY) was investigated in tobacco (Nicotiana tobaccum), tomato (Solanum lycopersicum) and potato (Solanum tuberosum) plants. In tobacco plants, infection of severe strains of PVY (PVYN or PVYN:O) induced conspicuous vein clearing and leaf deformation in the first three leaves above the inoculated leaves, but much milder symptoms in the upper leaves. The recovery phenotype was not obvious in tobacco plants infected with PVY strain that induce mild symptoms (PVYO). However, regardless of the virus strains, reduction in PVY RNA levels was similarly observed in the upper leaves of these plants. Removal of the first three leaves above the inoculated leaves interfered with the occurrence of recovery, suggesting that the signal(s) mediating the recovery is likely generated in these leaves. In PVYN or PVYN:O but not in PVYO-infected tobacco plants, the expression of PR-1a transcripts were correlated with the accumulation level of PVY RNA. Reduced level of PVY RNA in the upper leaves was also observed in infected tomato plants, whereas such phenomenon was not observed in potato plants. PVY-derived small RNAs were detected in both tobacco and potato plants and their accumulation levels were correlated with PVY RNA levels. Our results demonstrate that the recovery phenotype following PVY infection is host-specific and not necessarily associated with the expression of PR-1a and generation of PVY small RNAs. Full article
(This article belongs to the Section Viruses of Plants, Fungi and Protozoa)
Figures

Figure 1

Open AccessArticle
Evaluation of Virus Inactivation by Formaldehyde to Enhance Biosafety of Diagnostic Electron Microscopy
Viruses 2015, 7(2), 666-679; https://doi.org/10.3390/v7020666
Received: 22 December 2014 / Accepted: 4 February 2015 / Published: 10 February 2015
Cited by 10 | Viewed by 4324 | PDF Full-text (832 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Formaldehyde (FA) fixation of infectious samples is a well-established protocol in diagnostic electron microscopy of viruses. However, published experimental data that demonstrate virus inactivation by these fixation procedures are lacking. Usually, fixation is performed immediately before the sample preparation for microscopy. The fixation [...] Read more.
Formaldehyde (FA) fixation of infectious samples is a well-established protocol in diagnostic electron microscopy of viruses. However, published experimental data that demonstrate virus inactivation by these fixation procedures are lacking. Usually, fixation is performed immediately before the sample preparation for microscopy. The fixation procedure should transform viruses in a non–infectious but nonetheless structurally intact form in order to allow a proper diagnosis based on morphology. FA provides an essential advantage in comparison to other disinfectants, because it preserves the ultrastructure of biological material without interfering significantly with the preparation (i.e., the negative staining) and the detection of viruses. To examine the efficiency of FA inactivation, we used Vaccinia virus, Human adenovirus and Murine norovirus as models and treated them with FA under various conditions. Critical parameters for the inactivation efficiency were the temperature, the duration of the FA treatment, and the resistance of the virus in question. Our results show that FA inactivation at low temperature (4 °C) bears a high risk of incomplete inactivation. Higher temperatures (25 °C) are more efficient, although they still require rather long incubation times to fully inactivate a complex and highly robust virus like Vaccinia. A protocol, which applied 2% buffered FA for 60 min and a temperature–shift from 25 to 37 °C after 30 min was efficient for the complete inactivation of all test viruses, and therefore has the potential to improve both biosafety and speed of diagnostic electron microscopy. Full article
(This article belongs to the Special Issue Electron Microscopy in Virus Diagnostics and Research)
Figures

Figure 1

Open AccessArticle
Ageratum enation virus—A Begomovirus of Weeds with the Potential to Infect Crops
Viruses 2015, 7(2), 647-665; https://doi.org/10.3390/v7020647
Received: 10 December 2014 / Accepted: 21 January 2015 / Published: 10 February 2015
Cited by 9 | Viewed by 2737 | PDF Full-text (2187 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Samples of two Ageratum conyzoides, one Sonchus oleraceus and one turnip (Brassica rapa var. rapa) exhibiting virus-like symptoms were collected from Pakistan and Nepal. Full-length begomovirus clones were obtained from the four plant samples and betasatellite clones from three of [...] Read more.
Samples of two Ageratum conyzoides, one Sonchus oleraceus and one turnip (Brassica rapa var. rapa) exhibiting virus-like symptoms were collected from Pakistan and Nepal. Full-length begomovirus clones were obtained from the four plant samples and betasatellite clones from three of these. The begomovirus sequences were shown to be isolates of Ageratum enation virus (AEV) with greater than 89.1% nucleotide sequence identity to the 26 AEV sequences available in the databases. The three betasatellite sequences were shown to be isolates of Ageratum yellow leaf curl betasatellite (AYLCB) with greater than 90% identity to the 18 AYLCB sequences available in the databases. The AEV sequences were shown to fall into two distinct strains, for which the names Nepal (consisting of isolates from Nepal, India, and Pakistan—including the isolates identified here) and India (isolates occurring only in India) strains are proposed. For the clones obtained from two AEV isolates, with their AYLCB, infectivity was shown by Agrobacterium-mediated inoculation to Nicotiana benthamiana, N. tabacum, Solanum lycopersicon and A. conyzoides. N. benthamiana plants infected with AEV alone or betasatellite alone showed no symptoms. N. benthamiana plants infected with AEV with its associated betasatellite showed leaf curl symptoms. The findings show that AEV is predominantly a virus of weeds that has the capacity to infect crops. AYLCB appears to be the common partner betasatellite of AEV and is associated with diseases with a range of very different symptoms in the same plant species. The inability to satisfy Koch’s postulates with the cloned components of isolate SOL in A. conyzoides suggests that the etiology may be more complex than a single virus with a single betasatellite. Full article
(This article belongs to the Special Issue Advances in Gene Technology and Resistance to Viruses)
Figures

Figure 1

Open AccessReview
Engineering Viroid Resistance
Viruses 2015, 7(2), 634-646; https://doi.org/10.3390/v7020634
Received: 13 January 2015 / Accepted: 30 January 2015 / Published: 10 February 2015
Cited by 9 | Viewed by 2496 | PDF Full-text (470 KB) | HTML Full-text | XML Full-text
Abstract
Viroids are non-encapsidated, non-coding, circular, single-stranded RNAs (ssRNAs). They are classified into the families Pospiviroidae and Avsunviroidae, whose members replicate in the nucleus and chloroplast of plant cells, respectively. Viroids have a wide host range, including crop and ornamental plants, and can [...] Read more.
Viroids are non-encapsidated, non-coding, circular, single-stranded RNAs (ssRNAs). They are classified into the families Pospiviroidae and Avsunviroidae, whose members replicate in the nucleus and chloroplast of plant cells, respectively. Viroids have a wide host range, including crop and ornamental plants, and can cause devastating diseases with significant economic losses. Thus, several viroids are world-wide, classified as quarantine pathogens and, hence, there is an urgent need for the development of robust antiviroid strategies. RNA silencing-based technologies seem to be a promising tool in this direction. Here, we review the recent advances concerning the complex interaction of viroids with the host’s RNA silencing machinery, evaluate past and present antiviroid approaches, and finally suggest alternative strategies that could potentially be employed in the future in order to achieve transgenic and non-transgenic viroid-free plants. Full article
(This article belongs to the Special Issue Gene Technology and Resistance to Viruses - Reviews)
Open AccessReview
KSHV ORF57, a Protein of Many Faces
Viruses 2015, 7(2), 604-633; https://doi.org/10.3390/v7020604
Received: 29 November 2014 / Accepted: 2 February 2015 / Published: 10 February 2015
Cited by 14 | Viewed by 2667 | PDF Full-text (2013 KB) | HTML Full-text | XML Full-text
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) ORF57 protein (also known as mRNA transcript accumulation (Mta)) is a potent posttranscriptional regulator essential for the efficient expression of KSHV lytic genes and productive KSHV replication. ORF57 possesses numerous activities that promote the expression of viral genes, including [...] Read more.
Kaposi’s sarcoma-associated herpesvirus (KSHV) ORF57 protein (also known as mRNA transcript accumulation (Mta)) is a potent posttranscriptional regulator essential for the efficient expression of KSHV lytic genes and productive KSHV replication. ORF57 possesses numerous activities that promote the expression of viral genes, including the three major functions of enhancement of RNA stability, promotion of RNA splicing, and stimulation of protein translation. The multifunctional nature of ORF57 is driven by its ability to interact with an array of cellular cofactors. These interactions are required for the formation of ORF57-containing ribonucleoprotein complexes at specific binding sites in the target transcripts, referred as Mta-responsive elements (MREs). Understanding of the ORF57 protein conformation has led to the identification of two structurally-distinct domains within the ORF57 polypeptide: an unstructured intrinsically disordered N-terminal domain and a structured α-helix-rich C-terminal domain. The distinct structures of the domains serve as the foundation for their unique binding affinities: the N-terminal domain mediates ORF57 interactions with cellular cofactors and target RNAs, and the C-terminal domain mediates ORF57 homodimerization. In addition, each domain has been found to contribute to the stability of ORF57 protein in infected cells by counteracting caspase- and proteasome-mediated degradation pathways. Together, these new findings provide insight into the function and biological properties of ORF57 in the KSHV life cycle and pathogenesis. Full article
(This article belongs to the Special Issue Kaposi's Sarcoma-Associated Herpesvirus) Printed Edition available
Figures

Figure 1

Open AccessArticle
Mutations in the Reverse Transcriptase and Protease Genes of Human Immunodeficiency Virus-1 from Antiretroviral Naïve and Treated Pediatric Patients
Viruses 2015, 7(2), 590-603; https://doi.org/10.3390/v7020590
Received: 29 November 2014 / Accepted: 2 February 2015 / Published: 10 February 2015
Cited by 5 | Viewed by 2448 | PDF Full-text (3249 KB) | HTML Full-text | XML Full-text
Abstract
The success of highly active antiretroviral therapy (HAART) is challenged by the emergence of resistance-associated mutations in human immunodeficiency virus-1 (HIV-1). In this study, resistance associated mutations in the reverse transcriptase (RT) and protease (PR) genes in antiretroviral therapy (ART) naïve and treated [...] Read more.
The success of highly active antiretroviral therapy (HAART) is challenged by the emergence of resistance-associated mutations in human immunodeficiency virus-1 (HIV-1). In this study, resistance associated mutations in the reverse transcriptase (RT) and protease (PR) genes in antiretroviral therapy (ART) naïve and treated HIV-1 infected pediatric patients from North India were evaluated. Genotyping was successfully performed in 46 patients (30 ART naive and 16 treated) for the RT gene and in 53 patients (27 ART naive and 26 treated) for PR gene and mutations were identified using Stanford HIV Drug Resistance Database. A major drug resistant mutation in RT gene, L74I (NRTI), and two such mutations, K101E and G190A (NNRTI), were observed in two ART naïve patients, while M184V was detected in two ART treated patients. Overall, major resistance associated mutations in RT gene were observed in nine (30%) and seven (36%) of ART naïve and treated children respectively. Minor mutations were identified in PR gene in five children. Few non-clade C viral strains (≈30%) were detected, although subtype C was most predominant. The screening of ART naïve children for mutations in HIV-1 RT and protease genes, before and after initiation of ART is desirable for drug efficacy and good prognosis. Full article
(This article belongs to the Special Issue Advances in Gene Technology and Resistance to Viruses)
Figures

Figure 1

Open AccessArticle
Elevated Cytokines, Thrombin and PAI-1 in Severe HCPS Patients Due to Sin Nombre Virus
Viruses 2015, 7(2), 559-589; https://doi.org/10.3390/v7020559
Received: 6 November 2014 / Accepted: 3 February 2015 / Published: 10 February 2015
Cited by 12 | Viewed by 3175 | PDF Full-text (1877 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Sin Nombre Hantavirus (SNV, Bunyaviridae Hantavirus) is a Category A pathogen that causes Hantavirus Cardiopulmonary Syndrome (HCPS) with case fatality ratios generally ranging from 30% to 50%. HCPS is characterized by vascular leakage due to dysregulation of the endothelial barrier function. The [...] Read more.
Sin Nombre Hantavirus (SNV, Bunyaviridae Hantavirus) is a Category A pathogen that causes Hantavirus Cardiopulmonary Syndrome (HCPS) with case fatality ratios generally ranging from 30% to 50%. HCPS is characterized by vascular leakage due to dysregulation of the endothelial barrier function. The loss of vascular integrity results in non-cardiogenic pulmonary edema, shock, multi-organ failure and death. Using Electric Cell-substrate Impedance Sensing (ECIS) measurements, we found that plasma samples drawn from University of New Mexico Hospital patients with serologically-confirmed HCPS, induce loss of cell-cell adhesion in confluent epithelial and endothelial cell monolayers grown in ECIS cultureware. We show that the loss of cell-cell adhesion is sensitive to both thrombin and plasmin inhibitors in mild cases, and to thrombin only inhibition in severe cases, suggesting an increasing prothrombotic state with disease severity. A proteomic profile (2D gel electrophoresis and mass spectrometry) of HCPS plasma samples in our cohort revealed robust antifibrinolytic activity among terminal case patients. The prothrombotic activity is highlighted by acute ≥30 to >100 fold increases in active plasminogen activator inhibitor (PAI-1) which, preceded death of the subjects within 48 h. Taken together, this suggests that PAI-1 might be a response to the severe pathology as it is expected to reduce plasmin activity and possibly thrombin activity in the terminal patients. Full article
(This article belongs to the Section Animal Viruses)
Figures

Figure 1

Open AccessArticle
HIV-1 Induced Nuclear Factor I-B (NF-IB) Expression Negatively Regulates HIV-1 Replication through Interaction with the Long Terminal Repeat Region
Viruses 2015, 7(2), 543-558; https://doi.org/10.3390/v7020543
Received: 17 November 2014 / Revised: 12 January 2015 / Accepted: 26 January 2015 / Published: 5 February 2015
Cited by 7 | Viewed by 2453 | PDF Full-text (883 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Background: Retroviruses rely on host factors for cell entry, replication, transcription, and other major steps during their life cycle. Human Immunodeficiency Virus-1 (HIV-1) is well known for utilizing a plethora of strategies to evade the host immune response, including the establishment of latent [...] Read more.
Background: Retroviruses rely on host factors for cell entry, replication, transcription, and other major steps during their life cycle. Human Immunodeficiency Virus-1 (HIV-1) is well known for utilizing a plethora of strategies to evade the host immune response, including the establishment of latent infection within a subpopulation of susceptible cells. HIV-1 also manipulates cellular factors in latently infected cells and persists for long periods of time, despite the presence of successful highly active antiretroviral therapy (HAART). Results: In this study we demonstrate that Nuclear Factor-IB (NF-IB) is induced during HIV-1 infection and its expression negatively impacts viral replication. During HIV-1 infection in peripheral blood mononuclear cells (PBMCs), and the T cell line, Jurkat or during induction of virus replication in latently infected cells, ACH2 and J1.1, we observed a time-dependent alteration in NF-IB expression pattern that correlated with HIV-1 viral expression. Using the Chip assay, we observed an association of NF-IB with the long terminal repeat region of HIV-1 (LTR) (-386 to -453 nt), and this association negatively correlated with HIV-1 transcription. Furthermore, knock-down of NF-IB levels in J1.1 cells resulted in an increase of HIV-1 levels. Knock-down of NF-IB levels in J-Lat-Tat-GFP (A1), (a Jurkat cell GFP reporter model for latent HIV-1 infection) resulted in an increase in GFP levels, indicating a potential negative regulatory role of NF-IB in HIV-1 replication. Conclusion: Overall, our results suggest that NF-IB may play a role in intrinsic antiretroviral defenses against HIV-1. These observations may offer new insights into the correlation of the latently infected host cell types and HIV-1, and help to define new therapeutic approaches for triggering the switch from latency to active replication thereby eliminating HIV-1 latent infection. Full article
Figures

Figure 1

Open AccessArticle
Comparative Analysis of Glycoprotein B (gB) of Equine Herpesvirus Type 1 and Type 4 (EHV-1 and EHV-4) in Cellular Tropism and Cell-to-Cell Transmission
Viruses 2015, 7(2), 522-542; https://doi.org/10.3390/v7020522
Received: 3 December 2014 / Revised: 4 January 2015 / Accepted: 27 January 2015 / Published: 3 February 2015
Cited by 7 | Viewed by 3086 | PDF Full-text (1848 KB) | HTML Full-text | XML Full-text
Abstract
Glycoprotein B (gB) plays an important role in alphaherpesvirus cellular entry and acts in concert with gD and the gH/gL complex. To evaluate whether functional differences exist between gB1 and gB4, the corresponding genes were exchanged between the two viruses. The gB4-containing-EHV-1 (EHV-1_gB4) [...] Read more.
Glycoprotein B (gB) plays an important role in alphaherpesvirus cellular entry and acts in concert with gD and the gH/gL complex. To evaluate whether functional differences exist between gB1 and gB4, the corresponding genes were exchanged between the two viruses. The gB4-containing-EHV-1 (EHV-1_gB4) recombinant virus was analyzed for growth in culture, cell tropism, and cell entry rivaling no significant differences when compared to parental virus. We also disrupted a potential integrin-binding motif, which did not affect the function of gB in culture. In contrast, a significant reduction of plaque sizes and growth kinetics of gB1-containing-EHV-4 (EHV-4_gB1) was evident when compared to parental EHV-4 and revertant viruses. The reduction in virus growth may be attributable to the loss of functional interaction between gB and the other envelope proteins involved in virus entry, including gD and gH/gL. Alternatively, gB4 might have an additional function, required for EHV-4 replication, which is not fulfilled by gB1. In conclusion, our results show that the exchange of gB between EHV-1 and EHV-4 is possible, but results in a significant attenuation of virus growth in the case of EHV-4_gB1. The generation of stable recombinant viruses is a valuable tool to address viral entry in a comparative fashion and investigate this aspect of virus replication further. Full article
(This article belongs to the Special Issue Viral Glycoprotein Incorporation)
Figures

Figure 1

Open AccessReview
Understanding Ebola Virus Transmission
Viruses 2015, 7(2), 511-521; https://doi.org/10.3390/v7020511
Received: 7 December 2014 / Revised: 21 January 2015 / Accepted: 29 January 2015 / Published: 3 February 2015
Cited by 28 | Viewed by 7746 | PDF Full-text (564 KB) | HTML Full-text | XML Full-text
Abstract
An unprecedented number of Ebola virus infections among healthcare workers and patients have raised questions about our understanding of Ebola virus transmission. Here, we explore different routes of Ebola virus transmission between people, summarizing the known epidemiological and experimental data. From this data, [...] Read more.
An unprecedented number of Ebola virus infections among healthcare workers and patients have raised questions about our understanding of Ebola virus transmission. Here, we explore different routes of Ebola virus transmission between people, summarizing the known epidemiological and experimental data. From this data, we expose important gaps in Ebola virus research pertinent to outbreak situations. We further propose experiments and methods of data collection that will enable scientists to fill these voids in our knowledge about the transmission of Ebola virus. Full article
(This article belongs to the collection Advances in Ebolavirus, Marburgvirus, and Cuevavirus Research)
Figures

Figure 1

Open AccessCommunication
Multiple Regions of Kaposi’s Sarcoma-Associated Herpesvirus ORF59 RNA are Required for Its Expression Mediated by Viral ORF57 and Cellular RBM15
Viruses 2015, 7(2), 496-510; https://doi.org/10.3390/v7020496
Received: 19 December 2014 / Revised: 15 January 2015 / Accepted: 28 January 2015 / Published: 3 February 2015
Cited by 10 | Viewed by 2342 | PDF Full-text (1129 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
KSHV ORF57 (MTA) promotes RNA stability of ORF59, a viral DNA polymerase processivity factor. Here, we show that the integrity of both ORF59 RNA ends is necessary for ORF57-mediated ORF59 expression and deletion of both 5’ and 3’ regions, or one end region [...] Read more.
KSHV ORF57 (MTA) promotes RNA stability of ORF59, a viral DNA polymerase processivity factor. Here, we show that the integrity of both ORF59 RNA ends is necessary for ORF57-mediated ORF59 expression and deletion of both 5’ and 3’ regions, or one end region with a central region, of ORF59 RNA prevents ORF57-mediated translation of ORF59. The ORF59 sequence between nt 96633 and 96559 resembles other known MTA-responsive elements (MREs). ORF57 specifically binds to a stem-loop region from nt 96596–96572 of the MRE, which also binds cellular RBM15. Internal deletion of the MRE from ORF59 led to poor export, but accumulation of nuclear ORF59 RNA in the presence of ORF57 or RBM15. Despite of being translatable in the presence of ORF57, this deletion mutant exhibits translational defect in the presence of RBM15. Together, our results provide novel insight into the roles of ORF57 and RBM15 in ORF59 RNA accumulation and protein translation. Full article
(This article belongs to the Special Issue Kaposi's Sarcoma-Associated Herpesvirus) Printed Edition available
Figures

Figure 1

Open AccessArticle
Bovine Lactoferrin Inhibits Toscana Virus Infection by Binding to Heparan Sulphate
Viruses 2015, 7(2), 480-495; https://doi.org/10.3390/v7020480
Received: 1 December 2014 / Accepted: 23 January 2015 / Published: 29 January 2015
Cited by 10 | Viewed by 2475 | PDF Full-text (892 KB) | HTML Full-text | XML Full-text
Abstract
Toscana virus is an emerging sandfly-borne bunyavirus in Mediterranean Europe responsible for neurological diseases in humans. It accounts for about 80% of paediatric meningitis cases during the summer. Despite the important impact of Toscana virus infection-associated disease on human health, currently approved vaccines [...] Read more.
Toscana virus is an emerging sandfly-borne bunyavirus in Mediterranean Europe responsible for neurological diseases in humans. It accounts for about 80% of paediatric meningitis cases during the summer. Despite the important impact of Toscana virus infection-associated disease on human health, currently approved vaccines or effective antiviral treatments are not available. In this research, we have analyzed the effect of bovine lactoferrin, a bi-globular iron-binding glycoprotein with potent antimicrobial and immunomodulatory activities, on Toscana virus infection in vitro. Our results showed that lactoferrin was capable of inhibiting Toscana virus replication in a dose-dependent manner. Results obtained when lactoferrin was added to the cells during different phases of viral infection showed that lactoferrin was able to prevent viral replication when added during the viral adsorption step or during the entire cycle of virus infection, demonstrating that its action takes place in an early phase of viral infection. In particular, our results demonstrated that the anti-Toscana virus action of lactoferrin took place on virus attachment to the cell membrane, mainly through a competition for common glycosaminoglycan receptors. These findings provide further insights on the antiviral activity of bovine lactoferrin. Full article
(This article belongs to the Section Antivirals & Vaccines)
Figures

Figure 1

Open AccessArticle
In Search of Pathogens: Transcriptome-Based Identification of Viral Sequences from the Pine Processionary Moth (Thaumetopoea pityocampa)
Viruses 2015, 7(2), 456-479; https://doi.org/10.3390/v7020456
Received: 29 November 2014 / Revised: 29 December 2014 / Accepted: 13 January 2015 / Published: 23 January 2015
Cited by 6 | Viewed by 3174 | PDF Full-text (1928 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Thaumetopoea pityocampa (pine processionary moth) is one of the most important pine pests in the forests of Mediterranean countries, Central Europe, the Middle East and North Africa. Apart from causing significant damage to pinewoods, T. pityocampa occurrence is also an issue for public [...] Read more.
Thaumetopoea pityocampa (pine processionary moth) is one of the most important pine pests in the forests of Mediterranean countries, Central Europe, the Middle East and North Africa. Apart from causing significant damage to pinewoods, T. pityocampa occurrence is also an issue for public and animal health, as it is responsible for dermatological reactions in humans and animals by contact with its irritating hairs. High throughput sequencing technologies have allowed the fast and cost-effective generation of genetic information of interest to understand different biological aspects of non-model organisms as well as the identification of potential pathogens. Using these technologies, we have obtained and characterized the transcriptome of T. pityocampa larvae collected in 12 different geographical locations in Turkey. cDNA libraries for Illumina sequencing were prepared from four larval tissues, head, gut, fat body and integument. By pooling the sequences from Illumina platform with those previously published using the Roche 454-FLX and Sanger methods we generated the largest reference transcriptome of T. pityocampa. In addition, this study has also allowed identification of possible viral pathogens with potential application in future biocontrol strategies. Full article
(This article belongs to the Special Issue Insect Viruses and Their Use for Microbial Pest Control)
Figures

Figure 1

Viruses EISSN 1999-4915 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top