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 4, Issue 6 (June 2012), Pages 924-1033

  • 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 1-6
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle Evaluation of Different Antiretroviral Drug Protocols on Naturally Infected Feline Immunodeficiency Virus (FIV) Cats in the late Phase of the Asymptomatic Stage of Infection
Viruses 2012, 4(6), 924-939; doi:10.3390/v4060924
Received: 1 May 2012 / Revised: 14 May 2012 / Accepted: 24 May 2012 / Published: 30 May 2012
PDF Full-text (603 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this study was to evaluate the efficacy of the antiretrovirals: Zidovudine (ZDV) alone; ZDV + Recombinant Human Interferon-α (rHuIFN-α); ZDV + Lamivudine (3TC) and ZDV + valproic acid (Valp) on naturally feline immunodeficiency virus (FIV)-infected cats, in the
[...] Read more.
The aim of this study was to evaluate the efficacy of the antiretrovirals: Zidovudine (ZDV) alone; ZDV + Recombinant Human Interferon-α (rHuIFN-α); ZDV + Lamivudine (3TC) and ZDV + valproic acid (Valp) on naturally feline immunodeficiency virus (FIV)-infected cats, in the late phase of the asymptomatic stage of infection. The follow-up was performed over one year, through clinical evaluation and the determination of viral loads and CD4+/CD8+ ratios. Neurological signs were studied by visual and auditory evoked potentials (VEP, AEP) and the responses were abnormal in 80% of the FIV-infected cats. After one year, an improvement in VEP and AEP was observed in the ZDV + Valp group and a worsening in the group receiving ZDV + rHuIFN-α. The CD4+/CD8+ ratio showed a significant increase (both intra and inter-groups) only in ZDV and ZDV + 3TC, between their pre-treatment and one year values, as well as among the other groups. Viral load only showed a significant decrease in ZDV and ZDV + 3TC groups, when comparing the values at one year of treatment vs. pre-treatment values and when the different groups were compared. In addition, the viral load decrease was significantly more pronounced in the ZDV + 3TC vs. ZDV group. We conclude that ZDV and ZDV + 3TC produce significant reductions in viral load and stimulate a recovery of the CD4+/CD8+ ratio, compared with the other protocols. It is clear that the addition of 3TC resulted in a greater reduction in viral load than use of ZDV as a single drug. Therefore, the combination ZDV + 3TC could be more effective than the sole use of ZDV. Full article
(This article belongs to the Special Issue Feline Retroviruses)
Figures

Open AccessArticle Analysis of Sequence Polymorphism and Population Structure of Tomato chlorotic dwarf viroid and Potato spindle tuber viroid in Viroid-Infected Tomato Plants
Viruses 2012, 4(6), 940-953; doi:10.3390/v4060940
Received: 11 April 2012 / Revised: 15 May 2012 / Accepted: 30 May 2012 / Published: 5 June 2012
Cited by 4 | PDF Full-text (988 KB) | HTML Full-text | XML Full-text
Abstract
The sequence polymorphism and population structure of Tomato chlorotic dwarf viroid (TCDVd) (isolate Trust) and Potato tuber spindle viroid (PSTVd) (isolate FN) in tomato plants were investigated. Of the 9 and 35 TCDVd clones sequenced from 2 different TCDVd-infected plants, 2 and 4
[...] Read more.
The sequence polymorphism and population structure of Tomato chlorotic dwarf viroid (TCDVd) (isolate Trust) and Potato tuber spindle viroid (PSTVd) (isolate FN) in tomato plants were investigated. Of the 9 and 35 TCDVd clones sequenced from 2 different TCDVd-infected plants, 2 and 4 sequence variants were identified, respectively, leading to a total of 4 sequence variants of 360 nucleotides in length. Variant I was identical to AF162131, the first TCDVd sequence to be reported, and the rest exhibited 1 to 3 nucleotide differences, all in the TR domain, from AF162131/variant I. Of the 33 and 29 PSTVd clones sequenced from 2 different PSTVd-infected plants, 8 and 9 sequence variants were found, respectively, leading to a total of 15 variants ranging in length from 356 to 359 nucleotides. The variant I was identical to EF044303, a PSTVd reported in Russia. The rest exhibited 1 to 11 nucleotide differences scattering in all five domains from EF044303/variant I. The results demonstrated for the first time that TCDVd, like many other viroids including PSTVd, exists in host plants as a collective group comprised of various sequence variants. However, in comparison to PSTVd, TCDVd is less polymorphic in tomato plants as fewer variants and lower haplotype/nucleotide diversities were observed. Full article
(This article belongs to the Special Issue Plant Viruses)
Open AccessArticle Administration of Fozivudine Tidoxil as a Single-Agent Therapeutic during Acute Feline Immunodeficiency Virus Infection Does Not Alter Chronic Infection
Viruses 2012, 4(6), 954-962; doi:10.3390/v4060954
Received: 12 April 2012 / Revised: 19 May 2012 / Accepted: 5 June 2012 / Published: 7 June 2012
Cited by 1 | PDF Full-text (215 KB) | HTML Full-text | XML Full-text
Abstract
Initiating combination antiretroviral therapy (ART) during acute HIV infection has been correlated with decreased viral set point and improved lymphocyte function. However, the long term effects of single-agent therapy administered only during the acute stage of infection (interrupted treatment) remain largely uncharacterized. In
[...] Read more.
Initiating combination antiretroviral therapy (ART) during acute HIV infection has been correlated with decreased viral set point and improved lymphocyte function. However, the long term effects of single-agent therapy administered only during the acute stage of infection (interrupted treatment) remain largely uncharacterized. In this study we provide longitudinal data using the feline immunodeficiency virus (FIV) model for HIV infection. Infected cats were treated with a prophylactic single-agent therapy, Fozivudine tidoxil (FZD), for six weeks, starting one day before infection. The initial acute infection study, reported elsewhere, demonstrated a decrease in plasma- and cell-associated viremia at two weeks post-infection (PI) in FZD-treated cats as compared to placebo-treated cats. We hypothesized that this early alteration in plasma- and cell-associated viremia would alter the virus set point and ultimately affect the outcome of chronic infection. Here we provide data at one, two and three years PI for plasma- and/or cell-associated viremia, total lymphocyte counts and CD4:CD8 ratios. There was no difference in viremia or cell counts between treated and nontreated groups at all time points tested. Contrary to our hypothesis, these results suggest that treatment with a single agent anti-retroviral drug during acute lentivirus infection does not significantly alter viral load and immune function during the chronic, asymptomatic stage of infection. Full article
(This article belongs to the Special Issue Feline Retroviruses)

Review

Jump to: Research

Open AccessReview Application of Live-Cell RNA Imaging Techniques to the Study of Retroviral RNA Trafficking
Viruses 2012, 4(6), 963-979; doi:10.3390/v4060963
Received: 11 May 2012 / Revised: 5 June 2012 / Accepted: 6 June 2012 / Published: 8 June 2012
Cited by 13 | PDF Full-text (488 KB) | HTML Full-text | XML Full-text
Abstract
Retroviruses produce full-length RNA that serves both as a genomic RNA (gRNA), which is encapsidated into virus particles, and as an mRNA, which directs the synthesis of viral structural proteins. However, we are only beginning to understand the cellular and viral factors that
[...] Read more.
Retroviruses produce full-length RNA that serves both as a genomic RNA (gRNA), which is encapsidated into virus particles, and as an mRNA, which directs the synthesis of viral structural proteins. However, we are only beginning to understand the cellular and viral factors that influence trafficking of retroviral RNA and the selection of the RNA for encapsidation or translation. Live cell imaging studies of retroviral RNA trafficking have provided important insight into many aspects of the retrovirus life cycle including transcription dynamics, nuclear export of viral RNA, translational regulation, membrane targeting, and condensation of the gRNA during virion assembly. Here, we review cutting-edge techniques to visualize single RNA molecules in live cells and discuss the application of these systems to studying retroviral RNA trafficking. Full article
(This article belongs to the Special Issue Frontiers in Imaging)
Open AccessReview Recent Progress in Studies of Arterivirus- and Coronavirus-Host Interactions
Viruses 2012, 4(6), 980-1010; doi:10.3390/v4060980
Received: 7 May 2012 / Revised: 30 May 2012 / Accepted: 14 June 2012 / Published: 19 June 2012
Cited by 19 | PDF Full-text (890 KB) | HTML Full-text | XML Full-text
Abstract
Animal coronaviruses, such as infectious bronchitis virus (IBV), and arteriviruses, such as porcine reproductive and respiratory syndrome virus (PRRSV), are able to manifest highly contagious infections in their specific native hosts, thereby arising in critical economic damage to animal industries. This review discusses
[...] Read more.
Animal coronaviruses, such as infectious bronchitis virus (IBV), and arteriviruses, such as porcine reproductive and respiratory syndrome virus (PRRSV), are able to manifest highly contagious infections in their specific native hosts, thereby arising in critical economic damage to animal industries. This review discusses recent progress in studies of virus-host interactions during animal and human coronavirus and arterivirus infections, with emphasis on IBV-host cell interactions. These interactions may be directly involved in viral replication or lead to the alteration of certain signaling pathways, such as cell stress response and innate immunity, to facilitate viral replication and pathogenesis. Full article
(This article belongs to the Special Issue Animal Arteriviruses and Coronaviruses)
Open AccessReview Mechanisms of Coronavirus Cell Entry Mediated by the Viral Spike Protein
Viruses 2012, 4(6), 1011-1033; doi:10.3390/v4061011
Received: 8 May 2012 / Revised: 13 June 2012 / Accepted: 14 June 2012 / Published: 20 June 2012
Cited by 57 | PDF Full-text (978 KB) | HTML Full-text | XML Full-text
Abstract
Coronaviruses are enveloped positive-stranded RNA viruses that replicate in the cytoplasm. To deliver their nucleocapsid into the host cell, they rely on the fusion of their envelope with the host cell membrane. The spike glycoprotein (S) mediates virus entry and is a primary
[...] Read more.
Coronaviruses are enveloped positive-stranded RNA viruses that replicate in the cytoplasm. To deliver their nucleocapsid into the host cell, they rely on the fusion of their envelope with the host cell membrane. The spike glycoprotein (S) mediates virus entry and is a primary determinant of cell tropism and pathogenesis. It is classified as a class I fusion protein, and is responsible for binding to the receptor on the host cell as well as mediating the fusion of host and viral membranes—A process driven by major conformational changes of the S protein. This review discusses coronavirus entry mechanisms focusing on the different triggers used by coronaviruses to initiate the conformational change of the S protein: receptor binding, low pH exposure and proteolytic activation. We also highlight commonalities between coronavirus S proteins and other class I viral fusion proteins, as well as distinctive features that confer distinct tropism, pathogenicity and host interspecies transmission characteristics to coronaviruses. Full article
(This article belongs to the Special Issue Animal Arteriviruses and Coronaviruses)

Journal Contact

MDPI AG
Viruses Editorial Office
St. Alban-Anlage 66, 4052 Basel, Switzerland
viruses@mdpi.com
Tel. +41 61 683 77 34
Fax: +41 61 302 89 18
Editorial Board
Contact Details Submit to Viruses
Back to Top