Archives of Virology最新文献

Using a high-throughput sequencing (HTS) approach, we report the discovery of a new poacevirus (family Potyviridae) in symptomatic wild oat (Avena fatua L.) plants collected near Bordeaux, France, in June 2023. A nearly complete genome sequence of 10,292 nucleotides (nt) was obtained. The genome encodes a large 3189-amino-acid (aa) polyprotein with all of the expected hallmarks of those of Potyviridae members. The 3' untranslated region (UTR) is 195 nt long, and the 5' UTR, whose sequence is likely missing a few terminal nucleotides despite repeated efforts at 5' RACE, is unusually long (531 nt), like that of triticum mosaic virus (TrMV). Pairwise sequence comparisons and phylogenetic analysis showed that the new virus is most closely related to TrMV and to Poaceae Liege poacevirus, a virus that was identified recently in Poaceae members in Belgium by metagenomics. The common name "wild oat poacevirus 1" (WOPV1) is proposed for this novel virus, which should be accommodated in a new species in the genus Poacevirus. Given that WOPV1 was identified in plants that were coinfected by several other viruses, no conclusions can be drawn at this stage about its potential pathogenicity.

Five lytic bacteriophages specific for Salmonella enterica and Escherichia coli were isolated from wastewater in Minnesota. These phages, designated vB_Sal_EH1, vB_Sal_EH2, vB_Sal_EH3, vB_Sal_EH4, and vB_Sal_EH7, were characterized, and their genomes were sequenced. Phylogenetic analysis showed that they grouped within the genus Epseptimavirus, with genome sizes ranging from 108,554 to 115,218 bp. All five phages exhibited lytic activity against both S. enterica and Shiga-toxin-producing E. coli O157:H7. Transposon mutagenesis of the host genome identified the outer membrane protein BtuB as essential for phage infection, suggesting that it is a putative receptor. Genome sequence comparisons revealed genetic loci that are variable among the isolated phages and potentially influence their host specificity and virulence.

Calcitriol, or vitamin D (Vit D), is known for promoting strong bones and its ability to modulate inflammation and support the immune system. It has also been reported to be a potent antiviral agent, but the underlying mechanisms behind the mode of action are still unclear. Newcastle disease virus (NDV) belongs to the family Paramyxoviridae and causes infectious diseases in numerous avian species. In the present study, we explored the use of calcitriol as an antiviral agent against NDV infection. Post-treatment with calcitriol (the most active form of Vit D) was found to inhibit NDV replication in chicken embryo fibroblast cells (DF-1) in a time-of-addition- and concentration-dependent manner. The titer of NDV in allantoic fluid exhibited a substantial decrease after administration of cholecalciferol (the less active form of Vit D) to a 9-day-old chicken embryo. In addition, the results demonstrated a significant modulation of galectin 3 gene expression after NDV infection. Cytokine profiling of DF-1 cells treated with calcitriol and aloe-emodin, a known modulator of galectin 3, revealed significant upregulation of pro-inflammatory cytokines. The study indicates that calcitriol modulates host proteins, affecting NDV replication. These findings suggest that calcitriol or Vit D has the potential to be developed as an alternative antiviral drug against NDV, warranting further investigation.

Campylobacter jejuni is a leading cause of foodborne illness worldwide. The application of bacteriophages offers a promising approach to specifically target and reduce C. jejuni contamination in food products. In this study, two C. jejuni phages were characterized, and their ability to inhibit bacterial growth in combination with ethylenediaminetetraacetic acid (EDTA) was investigated. Both phages exhibited tolerance to a wide range of temperature (4–60 °C) and pH (3-9). Phage vB_CjeM-PC10 and vB_CjeM-PC22 were found to have a latent period of 30 min and 20 min and a burst size of 7 and 35 PFU/cell, respectively. Phage vB_CjeM-PC10 has a linear double-stranded DNA (dsDNA) genome of 51,148 bp with 77 ORFs and 29% GC content. Phage vB_CjeM-PC22 has a circular dsDNA genome of 32,543 bp with 56 ORFs and 28% GC content. At 42 °C, the combination of these phages (MOI = 10) and EDTA decreased the count of viable C. jejuni by 5.2 log₁₀ and inhibited the regrowth of resistant cells for 48 h. At 4 °C, phage vB_CjeM-PC10 alone (MOI = 1000) reduced the count of viable C. jejuni by 3 log₁₀ in brain heart infusion (BHI) broth and 2 log₁₀ on chicken skin after incubation for 48 h. Although these phages were effective against C. jejuni, they cannot be utilized directly for food safety applications because they are lysogenic. Nevertheless, these findings expand the genome library of C. jejuni phages and enrich data resources by highlighting potential strategies for controlling C. jejuni infections.

Noroviruses (family Caliciviridae) are common causes of acute gastroenteritis worldwide. Multiple polymerase/capsid combinations have been identified among members of norovirus genogroup GII, at least 10 of which contain GII.P16 polymerase. During hospital-based surveillance (2003–2013) in Russia, we identified eight noroviruses with GII.P16 polymerase – five GII.3[P16], two GII.16[P16], and one GII.5[P16]. This is the first report of the nearly complete genome sequence of a rare recombinant GII.5[P.16] norovirus, which was found in the feces of a child in 2010. Phylogenetic analysis revealed that ORF1 and ORF2/3 of the strain GII.5[P.16]/RUS/Novosibirsk/Nsk-N490/2010 formed separate branches in clusters GII.P16 and GII.5, respectively.

In this study, a novel virus isolated from Nigrospora oryzae, tentatively named "Nigrospora oryzae mycovirus 1" (NoMyV1), was identified. NoMyV1 has a non-segmented dsRNA genome that is 2891 bp in length and contains two non-overlapping open reading frames (ORF1 and 2). ORF1 encodes a protein with sequence similarity to the putative capsid proteins or hypothetical proteins of other unclassified viruses, while ORF2 encodes an RNA-dependent RNA polymerase (RdRp). Sequence comparisons showed that NoMyV1 was most similar to Penicillium janczewskii Beauveria bassiana-like virus 1 (PjBblV1), with 76.12% amino acid sequence identity in the RdRp. In a phylogenetic analysis based on RdRp sequences, NoMyV1 was found to cluster with several other unclassified viruses for which a new genus, "Unirnavirus", which is distinct from the family Partitiviridae, has been proposed. Thus, we conclude that NoMyV1 is a novel member of the proposed genus "Unirnavirus".

Interleukin 1 receptor antagonist (IL1RN) is a competitive inhibitor of interleukin 1 (IL-1). Natural killer cells (NK cells) contribute to the elimination of viruses by their antiviral effector function, which depends on a balance between inhibitory and activating receptor genes such as NKG2D and NKG2A. Using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assays, the association of intronic single-nucleotide polymorphisms (SNPs) in these genes with viral infection were assessed in 111 patients with hepatitis E virus (HEV) infection and 222 HEV-naive healthy controls. An SNP in the IL1RN (VNTR) gene revealed allele 2 to be associated with protection against HEV infection (IL1RN *1/*1 vs. IL1RN *2/*2, OR = 0.26, 95% CI = 0.14–0.47, p < 0.001). Similarly, a polymorphism in the intronic region of NKG2A revealed an association with protection in a co-dominant model (A/A vs. A/G: OR = 0.40; 95% CI = 0.24–0.67; A/A vs. G/G: OR = 0.25; 95% CI = 0.10–0.57; p < 0.05) and an association with susceptibility in a dominant model (A/A + A/G vs. G/G: OR = 2.28; 95% CI = 1.06–4.93; p < 0.05) and a recessive model (AA vs. AG + GG: OR = 2.71; 95% CI = 1.66–4.48; p < 0.001). Our data suggest that genetic polymorphisms in host NKG2A and IL1RN have both protective and detrimental roles in HEV infection, although their impact on disease outcome remains unknown.

Multidrug-resistant infections are becoming increasingly prevalent worldwide. One of the fastest-emerging alternative and adjuvant therapies being proposed is phage therapy. Naturally isolated phages are used in the vast majority of phage therapy treatments today. Engineered phages are being developed to enhance the effectiveness of phage therapy, but concerns over their potential escape remain a salient issue. To address this problem, we designed a biocontained phage system based on conditional replication using amber stop codon suppression. This system can be easily installed on any natural phage with a known genome sequence. To test the system, we individually mutated the start codons of three essential capsid genes in phage φX174 to the amber stop codon (UAG). These phages were able to efficiently infect host cells expressing the amber initiator tRNA, which suppresses the amber stop codon and initiates translation at TAG stop codons. The amber phage mutants were also able to successfully infect host cells and reduce their population on solid agar and liquid culture but could not produce infectious particles in the absence of the amber initiator tRNA or complementing capsid gene. We did not detect any growth-inhibiting effects on E. coli strains known to lack a receptor for φX174 and we showed that engineered phages have a limited propensity for reversion. The approach outlined here may be useful to control engineered phage replication in both the lab and clinic.