Archives of Virology最新文献

A putative novel virus was identified in Agastache rugosa in China and tentatively named "Agastache rugosa-associated varicosavirus" (ARaVV). The nearly complete genome sequence of ARaVV was obtained through RNA sequencing (RNA-seq) and subsequent RT-PCR. The ARaVV genome consists of two negative-sense single-stranded RNA segments that are 6428 and 3862 nucleotides (nt) in size, respectively. RNA1 encodes a large polymerase (L), and RNA2 encodes a putative nucleocapsid protein (N), protein 2 (P2), and protein 3 (P3). The L protein shared the highest amino acid (aa) sequence identity (51.3%) with Erysimum virus 1 (EryV1, BK061766.1). The N, P2, and P3 shared the highest aa sequence identity (33.1%, 14.0%, and 24.2%) with Leucanthemum virus 1, Raphanus virus 1, and Spinach virus 1, respectively. Phylogenetic analysis based on amino acid sequences of the L protein showed that ARaVV clustered in a clade with the varicosaviruses, indicating that ARaVV is a putative new member of the genus Varicosavirus.

The ongoing COVID-19 pandemic is threatening human health globally. The development of effective drugs and vaccines against SARS-CoV-2 is hindered by the limited access to high-biosafety-level facilities. Although human coronavirus (HCoV) OC43, a low-pathogenic endemic human coronavirus, has been used as a surrogate virus for SARS-CoV-2 research, a standard technique for HCoV-OC43 culture and plaque titration has not been established. Our objective was to establish optimized culture and titration protocols for HCoV-OC43. The growth kinetics and permissibility to HCoV-OC43 infection of seven different cell lines were examined concurrently at two different temperatures, 33°C and 37°C. Cell lines exhibiting a cytopathic effect (CPE) were selected for plaque titration. No significant difference in the rate of cell growth was observed at the two temperatures tested. Interestingly, HCoV-OC43 was found not to be a high-temperature-sensitive virus, since it grew well at 37°C. Although RD, LLC-MK2, MRC-5, and HCT-8 cell lines supported virus growth with an obvious cytopathic effect and a high yield of virus after two days of infection, only RD cells were suitable for producing countable plaques. The incubation of the cells with 1.2% low-viscosity Avicel as an overlay medium at 37°C for 4 days appeared to promote clearer and sharper plaque morphology. However, further optimization of the plaque titration protocol is still required due to the continued observation of plaque size variation and hazy zones. We propose a cost-effective protocol for HCoV-OC43 culture and plaque titration that can be implemented at a standard conventional temperature without the need for additional special equipment.

Noroviruses are the most common cause of acute gastroenteritis (AGE) outbreaks in childcare centers and kindergartens. Their high transmissibility is partly due to their genetic diversity. AGE outbreaks that occurred in Seoul childcare centers and kindergartens from 2019 to 2022 were investigated, and 68 epidemiological reports prepared by public health centers in Seoul were used for data collection. In the three quarters of 2022, there were 40 outbreaks of AGE in Seoul childcare centers and kindergartens, which exceeded the 35 total outbreaks that occurred during the previous three years. The proportion of childcare centers and kindergartens with AGE outbreaks among all facilities in Seoul increased from 12.6% in 2019 to 58.8% in 2022. Noroviruses were the most common pathogens responsible for AGE outbreaks in these cases. From 2019 to 2021, norovirus GII.2 was the predominant genotype, and GII.4 was detected in about 25% of cases. However, in 2022, GII.4 became predominant and was detected in about 79% of cases. The attack rate and infection source of AGE outbreaks from 2019 to 2021 were not significantly different from those in 2022. In conclusion, the number of AGE outbreaks in Seoul childcare centers and kindergartens increased significantly, primarily because of increased norovirus GII.4 transmission in 2022.

Cytomegalovirus (CMV) is a pathogen that is common worldwide and is often present in individuals infected with human immunodeficiency virus (HIV). Pattern recognition receptors (PRRs) are host sensors that activate the immune response against infectious agents. However, it is unclear whether PRR single-nucleotide polymorphisms (SNPs) are associated with the occurrence of CMV DNAemia in subjects coinfected with HIV and CMV. HIV/CMV-coinfected patients with and without CMV DNAemia were recruited for this study. The DDX58 rs10813831 and IFIH1 (rs3747517 and rs1990760) polymorphisms were genotyped using the TaqMan Allelic Discrimination Assay, whereas the DDX58 rs12006123 and TLR3 (rs3775291 and rs3775296) SNPs were analyzed using a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay. A mutation present in at least one allele of the DDX58 rs12006123 SNP occurred at least two times more frequently in HIV/CMV-coinfected patients with CMV DNAemia than in coinfected subjects without CMV DNAemia (OR, 2.50; 95% CI, 1.33–4.68; p = 0.004, in the dominant model). A higher level of CMV DNAemia was observed in subjects who had the heterozygous (GA) or homozygous recessive (AA) genotype for the DDX58 rs12006123 SNP compared with those who had the wild-type (GG) genotype (p = 0.0003). Moreover, in subjects with a mutation detected in at least one allele of the DDX58 rs12006123 SNP, a lower serum IFN-β concentration was found compared with those who had a wild-type (GG) genotype for this polymorphism (p = 0.024). The DDX58 rs12006123 SNP is associated with CMV DNAemia in HIV/CMV-coinfected patients.

South Africa has a small but growing olive industry. Until now, no virological research has been carried out on this crop locally. Seventeen samples were collected from various olive cultivars from a single producer in the Stellenbosch growing area of South Africa. RNAseq was performed on total RNA, and the compositions of the metaviromes were determined. Olive leaf yellowing-associated virus was detected for the first time in South Africa, as well as four novel viruses from the family Closteroviridae and one each from the families Tymoviridae and Solemoviridae.

One of the actively developing areas of drug development is the creation of chimeric toxins, recombinant bifunctional molecules designed to affect target cells selectively. The prevalent approach involves fusing bacterial and plant toxins with molecules that facilitate targeted delivery. However, the therapeutic use of such toxins often encounters challenges associated with negative side effects. Concurrently, viruses encode proteins possessing toxin-like properties, exerting multiple effects on the vital activity of cells. In contrast to bacterial and plant toxins, the impact of viral proteins is typically milder, presenting a significant advantage by potentially reducing the likelihood of side effects. This review delineates the characteristics of extensively studied viral proteins with toxic and immunomodulatory properties and explores the prospects of incorporating them into chimeric toxins.

Polybasic amino acid residues at the hemagglutinin (HA) cleavage site are insufficient to induce the highly pathogenic phenotype of avian influenza viruses in chickens. In our previous study, an H7N7 avian influenza virus named “Vac2sub-P0”, which is nonpathogenic despite carrying polybasic amino acids at the HA cleavage site, was passaged in chick air sacs, and a virus with high intravenous pathogenicity, Vac2sub-P3, was obtained. Intranasal infection with Vac2sub-P3 resulted in limited lethality in chickens; therefore, in this study, this virus was further passaged in chicken lungs, and the resultant virus, Vac2sub-P3L4, acquired high intranasal pathogenicity. Experimental infection of chickens with recombinant viruses demonstrated that mutations in HA and neuraminidase (NA) found in consecutive passages were responsible for the increased pathogenicity. The HA and NA functions of Vac2sub-P3L4 were compared with those of the parental virus in vitro; the virus growth at 40 °C was faster, the binding affinity to a sialic acid receptor was lower, and the rate of release by NA from the cell surface was lower, suggesting that these changes enabled the virus to replicate efficiently in chickens with high intranasal pathogenicity. This study demonstrates that viruses that are highly pathogenic when administered intranasally require additional adaptations for increased pathogenicity to be highly lethal to intranasally infected chickens.

In this study, we completely sequenced the genome of a new member of the genus Alphaendornavirus, family Endornaviridae, from lima bean (Phaseolus lunatus), for which we propose the name "lima bean endornavirus 1" (LbEV1). The complete genome of LbEV1 consists of 15,265 nucleotides, including a stretch of 12 cytosine residues at its 3’ end, and contains a long single open reading frame (ORF) coding for a 4980-aa-long polyprotein. Analysis of the polyprotein sequence revealed the presence of four conserved functional domains (in order from the N- to C-terminus): viral helicase 1, peptidase _C97, glycosyltransferase_GTB-type, and viral RNA-dependent RNA polymerase (RdRP). The LbEV1 polyprotein showed the highest amino acid sequence similarity (63% identity and 98% coverage) to Phaseolus vulgaris endornavirus 3 (PvEV3) and also showed 42% identity (95% coverage) to Geranium carolinianum endornavirus. Phylogenetic analysis based on the viral RdRp domain showed that LbEV1 belongs to a subclade within the genus Alphaendornavirus that includes three other viruses infecting plants of the genus Phaseolus.

Bacteria belonging to the Bacillus cereus group are ubiquitous in nature, causing food spoilage and food poisoning cases. A bequatrovirus, vB-BcgM, belonging to the C3 cluster infecting B. cereus group members, was isolated and characterized. Its 160-kb linear dsDNA genome contains a number of replication-related coding sequences (CDSs) and displays a collinear relationship with that of the virulent phage B4, with variations in its structural and replication regions. vB-BcgM has a relatively broad host range, with the ability to infect 33.3% of the B. cereus group isolates tested, including B. cereus, B. thuringiensis, B. anthracis, B. paranthracis, B. mycoides, and B. cytotoxicus. Moreover, vB-BcgM displays efficient infection and high replication capacity. It was found that 96.5% of the virions complete the adsorption process within 5 min. The optimal multiplicity of infection (MOI) is 10^-7, and the burst size is 63 plaque-forming units (PFU)/cell. This phage showed stability over a broad pH range (4-12) and at temperatures up to 70 °C. Furthermore, vB-BcgM displays significant antibacterial effects in processed food matrices (ultra-high temperature [UHT] sterilized milk [GB 25190], UHT refrigerated milk [GB 25190], pasteurized milk [GB 19645], mashed meat, and cereals) and fresh foods (lettuce, apple, and potato). The antibacterial effects were found to be dependent on the dose of viral inoculum, incubation conditions (food matrix and temperature), and time. The data indicate that vB-BcgM has good potential as an antibacterial agent.