ISSN / EISSN : 19994915 / 19994915
Current Publisher: MDPI (10.3390)
Total articles ≅ 3,925
Google Scholar h5-index: 53
Latest articles in this journal
Viruses, Volume 11; doi:10.3390/v11121146
Abstract:Grapevine fanleaf virus (GFLV) and arabis mosaic virus (ArMV) are nepoviruses responsible for grapevine degeneration. They are specifically transmitted from grapevine to grapevine by two distinct ectoparasitic dagger nematodes of the genus Xiphinema. GFLV and ArMV move from cell to cell as virions through tubules formed into plasmodesmata by the self-assembly of the viral movement protein. Five surface-exposed regions in the coat protein called R1 to R5, which differ between the two viruses, were previously defined and exchanged to test their involvement in virus transmission, leading to the identification of region R2 as a transmission determinant. Region R4 (amino acids 258 to 264) could not be tested in transmission due to its requirement for plant systemic infection. Here, we present a fine-tuning mutagenesis of the GFLV coat protein in and around region R4 that restored the virus movement and allowed its evaluation in transmission. We show that residues T258, M260, D261, and R301 play a crucial role in virus transmission, thus representing a new viral determinant of nematode transmission.
Viruses, Volume 11; doi:10.3390/v11121147
Abstract:In a recent paper, Sarathkumara et al
Viruses, Volume 11; doi:10.3390/v11121148
Abstract:Sequence-independent amplification techniques have become important tools for virus discovery, metagenomics, and exploration of viral diversity at the global scale, especially in remote areas. Here, we describe the detection and genetic characterization of a novel gyrovirus, named GyV11, present in cloacal, oral, and blood samples from neotropical wild birds in French Guiana. The molecular epidemiology revealed the presence of GyV11 only in passerine birds from three different species at a low prevalence (0.73%). This is the first characterization and prevalence study of a gyrovirus carried out in resident wild bird populations in a remote region, and provides evidence of the fecal–oral route transmission and local circulation of the virus. The molecular phylogeny of gyroviruses reveals the existence of two distinct gyrovirus lineages in which GyV11 is phylogenetically distinct from previously reported gyroviruses. Furthermore, GyV11 is placed basal in the gyrovirus phylogeny, likely owing to its ancestral origin and marked divergence. This study also provides important insights into the ecology, epidemiology, and genomic features of gyroviruses in a remote neotropical rainforest. The pathogenesis of this virus in avian species or whether GyV11 can infect humans and/or chickens needs to be further investigated.
Viruses, Volume 11; doi:10.3390/v11121150
Abstract:Dear Drs. W. Katherine Yih, Martin Kulldorff, Jessica H. Leibler, David J. Friedman, and Daniel R. Brooks
Viruses, Volume 11; doi:10.3390/v11121139
Abstract:Grapevine fanleaf virus (GFLV) is responsible for a widespread disease in vineyards worldwide. Its genome is composed of two single-stranded positive-sense RNAs, which both show a high genetic diversity. The virus is transmitted from grapevine to grapevine by the ectoparasitic nematode Xiphinema index. Grapevines in diseased vineyards are often infected by multiple genetic variants of GFLV but no information is available on the molecular composition of virus variants retained in X. index following nematodes feeding on roots. In this work, aviruliferous X. index were fed on three naturally GFLV-infected grapevines for which the virome was characterized by RNAseq. Six RNA-1 and four RNA-2 molecules were assembled segregating into four and three distinct phylogenetic clades of RNA-1 and RNA-2, respectively. After 19 months of rearing, single and pools of 30 X. index tested positive for GFLV. Additionally, either pooled or single X. index carried multiple variants of the two GFLV genomic RNAs. However, the full viral genetic diversity found in the leaves of infected grapevines was not detected in viruliferous nematodes, indicating a genetic bottleneck. Our results provide new insights into the complexity of GFLV populations and the putative role of X. index as reservoirs of virus diversity.
Viruses, Volume 11; doi:10.3390/v11121142
Abstract:Atypical porcine pestivirus (APPV) is a newly recognized member of the Flaviviridae family. This novel porcine pestivirus was first described in 2015 in the USA, where it has been associated with congenital tremor type A-II in new-born piglets. APPV is widely distributed in domestic pigs in Europe and Asia. In this study, a virological survey was performed in Northern Italy to investigate the presence of APPV using molecular methods. Testing of 360 abortion samples from pig herds revealed two APPV strains from distinct provinces in the Lombardy region and testing of 430 wild boar blood samples revealed three strains, one from Lombardy and two from Emilia Romagna. The nucleotide sequencing of a fragment of the nonstructural protein 3-coding region revealed a high similarity to the previously detected European strains (Spanish, German, and Italian) of APPV.
Viruses, Volume 11; doi:10.3390/v11121143
Abstract:Bacteriophages of the significant veterinary pathogen Staphylococcus pseudintermedius are rarely described morphologically and genomically in detail, and mostly include phages of the Siphoviridae family. There is currently no taxonomical classification for phages of this bacterial species. Here we describe a new phage designated vB_SpsS_QT1, which is related to phage 2638A originally described as a Staphylococcus aureus phage. Propagating strain S. aureus 2854 of the latter was reclassified by rpoB gene sequencing as S. pseudintermedius 2854 in this work. Both phages have a narrow but different host range determined on 54 strains. Morphologically, both of them belong to the family Siphoviridae, share the B1 morphotype, and differ from other staphylococcal phage genera by a single long fibre at the terminus of the tail. The complete genome of phage vB_SpsS_QT1 was sequenced with the IonTorrent platform and expertly annotated. Its linear genome with cohesive ends is 43,029 bp long and encodes 60 predicted genes with the typical modular structure of staphylococcal siphophages. A global alignment found the genomes of vB_SpsS_QT1 and 2638A to share 84% nucleotide identity, but they have no significant similarity of nucleotide sequences with other phage genomes available in public databases. Based on the morphological, phylogenetic, and genomic analyses, a novel genus Fibralongavirus in the family Siphoviridae is described with phage species vB_SpsS_QT1 and 2638A.
Viruses, Volume 11; doi:10.3390/v11121144
Abstract:Feline infectious peritonitis (FIP) is a fatal immune-mediated disease of cats, induced by feline coronavirus (FCoV). A combination of as yet poorly understood host and viral factors combine to cause a minority of FCoV-infected cats to develop FIP. Clinicopathological features include fever, vasculitis, and serositis, with or without effusions; all of which indicate a pro-inflammatory state with cytokine release. As a result, primary immune organs, as well as circulating leukocytes, have thus far been of most interest in previous studies to determine the likely sources of these cytokines. Results have suggested that these tissues alone may not be sufficient to induce the observed inflammation. The current study therefore focussed on the liver and heart, organs with a demonstrated ability to produce cytokines and therefore with huge potential to exacerbate inflammatory processes. The IL-12:IL-10 ratio, a marker of the immune system’s inflammatory balance, was skewed towards the pro-inflammatory IL-12 in the liver of cats with FIP. Both organs were found to upregulate mRNA expression of the inflammatory triad of cytokines IL-1β, IL-6, and TNF-α in FIP. This amplifying step may be one of the missing links in the pathogenesis of this enigmatic disease.
Viruses, Volume 11; doi:10.3390/v11121145
Abstract:Lipids play a crucial role in the replication of porcine reproductive and respiratory syndrome virus (PRRSV), a porcine virus that is endemic throughout the world. However, little is known about the effect of fatty acids (FAs), a type of vital lipid, on PRRSV infection. In this study, we found that treatment with a FA biosynthetic inhibitor significantly inhibited PRRSV propagation, indicating the necessity of FAs for optimal replication of PRRSV. Further study revealed that 5′-adenosine monophosphate (AMP)-activated protein kinase (AMPK), a key kinase antagonizing FA biosynthesis, was strongly activated by PRRSV and the pharmacological activator of AMPK exhibited anti-PRRSV activity. Additionally, we found that acetyl-CoA carboxylase 1 (ACC1), the first rate-limiting enzyme in the FA biosynthesis pathway, was phosphorylated (inactive form) by PRRSV-activated AMPK, and active ACC1 was required for PRRSV proliferation, suggesting that the PRRSV infection induced the activation of the AMPK–ACC1 pathway, which was not conducive to PRRSV replication. This work provides new evidence about the mechanisms involved in host lipid metabolism during PRRSV infection and identifies novel potential antiviral targets for PRRSV.
Viruses, Volume 11; doi:10.3390/v11121140
Abstract:Bovine leukemia virus (BLV), which is closely related to human T-cell leukemia viruses, is the causative agent of enzootic bovine leukosis, the most common neoplastic disease of cattle. The transmembrane subunit of the BLV envelope glycoprotein, gp30, contains three completely conserved YXXL sequences that fit an endocytic sorting motif. The two N-terminal YXXL sequences are reportedly critical for viral infection. However, their actual function in the viral life cycle remains undetermined. Here, we identified the novel roles of each YXXL sequence. Syncytia formation ability was upregulated by a single mutation of the tyrosine (Tyr) residue in any of the three YXXL sequences, indicating that each YXXL sequence is independently able to regulate the fusion event. The alteration resulted from significantly high expression of gp51 on the cell surface, thereby decreasing the amount of gp51 in early endosomes and further revealing that the three YXXL sequences are independently required for internalization of the envelope (Env) protein, following transport to the cell surface. Moreover, the 2nd and 3rd YXXL sequences contributed to Env protein incorporation into the virion by functionally distinct mechanisms. Our findings provide new insights regarding the three YXXL sequences toward the BLV viral life cycle and for developing new anti-BLV drugs.