Virology Research Research Articles

Virtual indentation of the empty capsid of the minute virus of mice using a minimal coarse-grained model.

A minimal coarse-grained model for T=1 viral capsids assembled from 20 protein rigid trimers has been designed by extending a previously proposed form of the interaction energy written as a sum of anisotropic pairwise interactions between the trimeric capsomers. The extension of the model has been performed to properly account for the coupling between two internal coordinates: the one that measures the intercapsomer distance and the other that gives the intercapsomer dihedral angle. The model has been able to fit with less than a 10% error the atomic force microscopy (AFM) indentation experimental data for the empty capsid of the minute virus of mice (MVM), providing in this way an admissible picture of the main mechanisms behind the capsid deformations. In this scenario, the bending of the intercapsomer dihedral angle is the angular internal coordinate that can support larger deformations away from its equilibrium values, determining important features of the AFM indentation experiments as the elastic constants along the three symmetry axes of the capsid and the critical indentations. From the value of one of the parameters of our model, we conclude that trimers in the MVM must be quite oblate tops, in excellent agreement with their known structure. The transition from the linear to the nonlinear regimes sampled in the indentation process appears to be an interesting topic for future research in physical virology.

Abstract TMP8: Varicella Zoster Virus Infection in Children With Arterial Ischemic Stroke: The Chicken or the Egg?

Introduction: Serologic evidence of varicella zoster virus (VZV) infection has been associated with childhood arterial ischemic stroke (AIS). Questions of causality persist: does VZV infection cause AIS, or does AIS reactivate VZV? The Vascular effects of Infection in Pediatric Stroke (VIPS II) study aimed to examine this relationship. Methods: This North American 22-center prospective cohort study enrolled 205 children (28 days-18 years) with AIS (2017-2022). Blood samples were hyperacute (≤72hrs; n=194), acute (4-7 days; n=180) and convalescent (1-6 weeks; n=73). A virology research lab used ELISA to measure VZV IgM and IgG titers. A pediatric virologist (CG) interpreted the results and classified the evidence of infection. Low-level IgG seropositivity is consistent with prior vaccination/infection. Highly elevated IgM in hyperacute/acute samples indicated reactivation coincident with stroke . Rising IgG titers between hyperacute and convalescent samples, occasionally with a high IgM in convalescent sample, indicated reactivation after the stroke . Results: Median age (IQR) was 11.6 years (5.3, 15.6). All 205 cases were low-level IgG positive; 160 (78%) reported prior VZV vaccination and 3 reported remote chicken pox. Serologies for 15 (7.3%; 95% CI 4.1, 11.8%) indicated VZV reactivation coincident with stroke; prior VZV vaccination reported in 14 and unknown in one. Stroke etiology amongst these 15 was definite arteriopathy in 4 (27%), possible arteriopathy in 4 (27%), cardioembolic in 5 (33%), and idiopathic in 2 (13%) (compared to 37%, 37%, 10%, 14%, respectively, for the other 190). Among 73 with convalescent samples, 17 (23%) had VZV reactivation after stroke. All cases of VZV reactivation were asymptomatic zoster sine herpete (herpes zoster without rash). Conclusions: While stroke triggered VZV reactivation in 23% of cases, 7.3% had evidence of zoster sine herpete at the time of their stroke, implying a causal role. We could not distinguish antibodies to vaccine virus versus wild-type; these zoster cases could represent reactivation of vaccine virus or a break-through wild-type varicella infection. Either scenario would be unexpected in this current era of routine childhood VZV vaccination and low rates of pediatric chicken pox or zoster.

The Gain-of-Function Research in Virology: Concerns, Risks, and Benefits

Gain-of-function (GOF) research is biotechnological research that genetically modifies microbial gene products to enhance their biological function. The basic aim of this research is to elucidate the pathogenesis of infectious diseases, develop new vaccines and therapeutics, improve cancer treatments, and achieve specific goals by adding beneficial trait expression to the genome. Despite these significant potential benefits, GOF research can pose some important and serious biosafety risks. The main group of pathogens of concern in GOF research are respiratory viruses with pandemic potential. While laboratory accidents and ongoing discussions in recent years have raised important awareness that these studies should be carried out in high-safety laboratories, concerns about the results of these studies remain unclear due to the inadequacy or absence of mechanisms to prevent misuse for informal research, despite the strict controls in research funded by international organizations. The most important issue to be discussed is the need to establish regulations that ensure the sustainability of scientific studies and developments that can benefit humanity, as well as strict control or, if necessary, a moratorium on potentially risky research. Debates on the value, safety, ethics, and validity of GOF studies are still ongoing. In this article, it is aimed to examine the status of GOF research in virology, with examples from the current literature, together with benefit and risk perspectives.

Functional Impacts of Epitranscriptomic m6A Modification on HIV-1 Infection.

Epitranscriptomic RNA modifications play a crucial role in the posttranscriptional regulation of gene expression. N6-methyladenosine (m6A) is the most prevalent internal modification of eukaryotic RNA and plays a pivotal role in RNA fate. RNA m6A modification is regulated by a group of cellular proteins, methyltransferases (writers) and demethylases (erasers), which add and remove the methyl group from adenosine, respectively. m6A modification is recognized by a group of cellular RNA-binding proteins (readers) that specifically bind to m6A-modified RNA, mediating effects on RNA stability, splicing, transport, and translation. The functional significance of m6A modification of viral and cellular RNA is an active area of virology research. In this review, we summarize and analyze the current literature on m6A modification of HIV-1 RNA, the multifaceted functions of m6A in regulating HIV-1 replication, and the role of viral RNA m6A modification in evading innate immune responses to infection. Furthermore, we briefly discuss the future directions and therapeutic implications of mechanistic studies of HIV-1 epitranscriptomic modifications.

Virology-the path forward.

In the United States (US), biosafety and biosecurity oversight of research on viruses is being reappraised. Safety in virology research is paramount and oversight frameworks should be reviewed periodically. Changes should be made with care, however, to avoid impeding science that is essential for rapidly reducing and responding to pandemic threats as well as addressing more common challenges caused by infectious diseases. Decades of research uniquely positioned the US to be able to respond to the COVID-19 crisis with astounding speed, delivering life-saving vaccines within a year of identifying the virus. We should embolden and empower this strength, which is a vital part of protecting the health, economy, and security of US citizens. Herein, we offer our perspectives on priorities for revised rules governing virology research in the US.

Electron Microscopy Methods for Phage-Based Study.

Electron microscopy (EM) techniques play a vital role in virology research including phage discovery and their identification. The use of different staining protocols based on the concept of negative staining is one of the most important steps in the EM processing. This chapter will summarize the widely used EM protocols in phage research, their advantages, and limitations. Phage-based therapy, especially recently developed nanoparticle-phage conjugates, are expected to find clinical significance in theantimicrobial resistance (AMR) epidemic. EM techniques are important to characterize these conjugates and we will also discuss the methods here.

A Microsphere Immunoassay for the Quantitative Detection of Antigens in Cell Culture Supernatant.

Quantitative immunoassays, such as the traditional enzyme-linked immunosorbent assay (ELISA), are used to determine concentrations of an antigen in a matrix of unknown antigen concentration. Magnetic immunoassays, such as the Luminex xMAP technology, allow for the simultaneous detection of multiple analytes and offer heightened sensitivity, specificity, low sample volume requirements, and high-throughput capabilities. Here, we describe a quantitative immunoassay using the Luminex MAGPIX® System to determine the antigen concentration from liquid samples with unknown concentrations. In detail, we describe a newly developed assay for determining production yields of Drosophila S2-produced Marburg virus (MARV) glycoprotein in insect-cell-culture-derived supernatant. The potential applications of this assay could extend to the quantification of viral antigens in fluids derived from both in vitro and in vivo models infected with live MARV, thereby providing additional applications for virological research.

DVsc: An Automated Framework for Efficiently Detecting Viral Infection from Single-cell Transcriptomics Data.

Single-cell RNA sequencing (scRNA-seq) has emerged as a valuable tool for studying cellular heterogeneity in various fields, particularly in virological research. By studying the viral and cellular transcriptomes, the dynamics of viral infection can be investigated at a single-cell resolution. However, limited studies have been conducted to investigate whether RNA transcripts from clinical samples contain substantial amounts of viral RNAs, and a specific computational framework for efficiently detecting viral reads based on scRNA-seq data has not been developed. Hence, we introduce DVsc, an open-source framework for precise quantitative analysis of viral infection from single-cell transcriptomics data. When applied to approximately 200 diverse clinical samples that were infected by more than 10 different viruses, DVsc demonstrated high accuracy in systematically detecting viral infection across a wide array of cell types. This innovative bioinformatics pipeline could be crucial for addressing the potential effects of surreptitiously invading viruses on certain illnesses, as well as for designing novel medicines to target viruses in specific host cell subsets and evaluating the efficacy of treatment. DVsc supports the FASTQ format as an input and is compatible with multiple single-cell sequencing platforms. Moreover, it could also be applied to sequences from bulk RNA sequencing data. DVsc is available at http://62.234.32.33:5000/DVsc.

Development of a spotted sea bass (Lateolabrax maculatus) bulbus arteriosus cell line and its application to fish virology and immunology

The bulbus arteriosus tissue of teleosts, which is located at the forefront of the heart, is used to reduce the pulse pressure. In this study, we constructed a permanent cell line (LmAB) for the first time using bulbus arteriosus tissue from spotted sea bass (Lateolabrax maculatus). This cell line has been passaged more than 80 times. Currently, it can be subcultured in L-15 medium with 8 % fetal bovine serum added. The optimal fetal bovine serum concentration and culture temperature for LmAB cells at 62 passages are 20 % and 28 °C, respectively. This cell line consists predominantly of epithelial-like cells. We used 18S rRNA gene sequencing to confirm that LmAB cells originated from spotted sea bass. Karyotype analysis revealed that 43 % of LmAB cells in passage 63 had 48 chromosomes. Exogenous plasmid transfection revealed that LmAB cells can express the green fluorescent protein gene with a transfection efficiency of up to 40 %, indicating that these cells can be used for in vitro genetic research. LmAB cells showed susceptibility to nervous necrosis virus, largemouth bass ulcer syndrome virus, and infectious spleen and kidney necrosis virus, which results in severe cytopathic effects. PCR analysis verified that these viruses can replicate in LmAB cells, and analysis of cytoskeletal F-actin patterns verified that infected cells exhibit serious changes in their actin cytoskeleton. LmAB cells infected with these three viruses showed increased expressions of interferon signaling pathway genes (IFNd, IFNγ-rel, and ISG15), indicating that the host interferon signaling pathway participates in the antiviral immune response. These findings indicate that our newly developed LmAB cell line is a valuable resource for future research in genetics, virology, and immunology.

Comparison of quantitative PCR and digital PCR assays for quantitative detection of infectious bronchitis virus (IBV) genome

The quantitative polymerase chain reaction (qPCR) technique is an extensively used molecular tool for the detection and quantification of viral genome load. However, since the qPCR assay is a relative quantification method that relies on an external calibration curve it has a lower assay precision and sensitivity. The digital PCR (dPCR) technique is a good alternative to the qPCR assay as it offers highly precise and direct quantification of viral genome load in samples. In this study, performance characteristics such as the quantification range, sensitivity, precision, and specificity of the dPCR technique was compared to qPCR technique for the detection and quantification of IBV genome loads in serial dilutions of IBV positive plasmid DNA, and IBV infected chicken tissue and swab samples. The quantification range of the qPCR assay was wider than that of the dPCR assay, however dPCR had a higher sensitivity compared to qPCR. The precision of quantification of DNA in plasmid samples in terms of repeatability and reproducibility of results was higher when using the dPCR assay compared to qPCR assay. The quantification results of IBV genome load in infected samples by the qPCR and dPCR assays displayed a high correlation. Hence, our findings suggest that dPCR could be used in avian virology research for improved precision and sensitivity in detection and quantification of viral genome loads.

The Unknown Infection, or ‘Rožňava Disease’ in Czechoslovakia in 1951

This article analyses the scientific and ideological impact of the 1951 tick-borne encephalitis epidemic in Rožňava (Czechoslovakia). Scientists in Rožňava discovered the possibility of transmission of the tick-borne encephalitis virus through non-pasteurised milk. The article focuses on both the outbreak in Rožňava, with its social and ideological implications, and the subsequent virological research, which became a means of prestige and symbolic power for Czechoslovak scientists within the domestic and international scientific community. The article shows that an epidemic can become a tool of power. The Rožňava epidemic, although now forgotten, helped establish the institutional background for virological research in Czechoslovakia and was at the origin of the still cutting-edge knowledge of tick-borne encephalitis.

Optimization of a Protocol for Launching Grapevine Infection with the Biologically Active cDNA Clones of a Virus.

Grapevine leafroll disease (GLRD) is the most globally prevalent and destructive disease complex responsible for significant reductions in grape yield and quality as well as wine production. GLRD is associated with several positive-strand RNA viruses of the family Closteroviridae, designated as grapevine leafroll-associated viruses (GLRaVs). However, the specific etiological role of any of these GLRaVs in GLRD has not been demonstrated. Even though GLRaV-3 is considered the chief GLRD agent, little is known about the molecular, cellular, and pathological properties of this virus. Such a knowledge gap is due to multiple factors, including the unavailability of biologically active virus cDNA clones and the lack of reliable experimental systems for launching grapevine infection using such clones. In this work, we tested four methods for inoculating tissue-cultured grapevine plantlets with cDNA clones of GLRaV-3: (i) vacuum agro-infiltration; (ii) agro-pricking; (iii) agro-drenching; and (iv) agro-injection. We showed that vacuum agro-infiltration was the most effective of these methods. Furthermore, we examined the impacts of different experimental conditions on the survival and infectivity rate of grapevines after infiltration. To verify the infectivity rate for different treatments, we used RT-PCR, RT-qPCR, and Western blotting. We found that humidity plays a critical role in the survival of plantlets after agro-infiltration and that the use of RNA silencing suppressor and dormancy treatment both had strong effects on the infection rates. To our knowledge, the experimental protocol reported herein is the most effective system for launching the infection of grapevine using cDNA clones of grapevine viruses featuring up to a 70% infection rate. This system has strong potential to facilitate grapevine virology research including the fulfillment of Koch's postulates for GLRD and other major virus diseases as well as identifying the molecular, cellular, and pathological properties of GLRaVs and, potentially, other important grapevine viruses.

Analysing the interplay of environmental virology, public health, and sanitation: a comprehensive review from a Kenyan perspective.

This comprehensive review examines the interplay between environmental virology, public health, and sanitation in the unique context of Kenya. The review sheds light on the specific viral threats faced by the country, including waterborne viruses, zoonotic infections, and emerging viral diseases, and their implications for public health. It explores the prevailing public health challenges in Kenya associated with environmental viromics, such as infectious viral diseases, and the rising burden of other infectious particles. The role of sanitation in mitigating viral infections is highlighted, emphasising the importance of clean water supply, proper waste management, and hygienic practises. The review also presents strategies for strengthening environmental virology research in Kenya, including enhancing laboratory capacities and leveraging technological advancements. Furthermore, the policy implications and recommendations derived from the review emphasise the need for multi-sectoral collaboration, evidence-based decision-making, and long-term investments in infrastructure and behaviour change interventions. Implementing these strategies can enhance the understanding of environmental virology, improve public health outcomes, and ensure sustainable sanitation practises in Kenya, ultimately contributing to the well-being of the population and sustainable development.

Using autopsies to dissect COVID-19 pathogenesis.

The emergence of SARS-CoV-2 has resulted in millions of deaths as a result of COVID-19. Suitable models were missing at the beginning of the pandemic, and studies investigating disease pathogenesis relied on patients who had succumbed to COVID-19. Since then, autopsies of patients have substantially contributed to our understanding of the pathogenesis of COVID-19 and associated major organ complications. Here we summarize how autopsies have complemented experimental studies, mainly in animal models, and how they have facilitated critical knowledge of COVID-19 to improve daily clinical practice and develop therapeutic interventions. Employing advanced histopathologic and molecular genetic methods in post-mortem tissues, the COVID-19 pandemic has highlighted the importance of autopsies for virology research and clinical practice in current and emerging infectious diseases.

Transforming clinical virology with AI, machine learning and deep learning: a comprehensive review and outlook.

In the rapidly evolving field of clinical virology, technological advancements have always played a pivotal role in driving transformative changes. This comprehensive review delves into the burgeoning integration of artificial intelligence (AI), machine learning, and deep learning into virological research and practice. As we elucidate, these computational tools have significantly enhanced diagnostic precision, therapeutic interventions, and epidemiological monitoring. Through in-depth analyses of notable case studies, we showcase how algorithms can optimize viral genome sequencing, accelerate drug discovery, and offer predictive insights into viral outbreaks. However, with these advancements come inherent challenges, particularly in data security, algorithmic biases, and ethical considerations. Addressing these challenges head-on, we discuss potential remedial measures and underscore the significance of interdisciplinary collaboration between virologists, data scientists, and ethicists. Conclusively, this review posits an outlook that anticipates a symbiotic relationship between AI-driven tools and virology, heralding a new era of proactive and personalized patient care.

Phylogeographic Aspects of Bat Lyssaviruses in Europe: A Review.

During the last few decades, bat lyssaviruses have become the topic of intensive molecular and epidemiological investigations. Since ancient times, rhabdoviruses have caused fatal encephalitis in humans which has led to research into effective strategies for their eradication. Modelling of potential future cross-species virus transmissions forms a substantial component of the recent infection biology of rabies. In this article, we summarise the available data on the phylogeography of both bats and lyssaviruses in Europe and the adjacent reg ions, especially in the contact zone between the Palearctic and Ethiopian realms. Within these zones, three bat families are present with high potential for cross-species transmission and the spread of lyssaviruses in Phylogroup II to Europe (part of the western Palearctic). The lack of effective therapies for rabies viruses in Phylogroup II and the most divergent lyssaviruses generates impetus for additional phylogenetic and virological research within this geographical region.

Detection of single nucleotide polymorphisms in virus genomes assembled from high-throughput sequencing data: large-scale performance testing of sequence analysis strategies.

Recent developments in high-throughput sequencing (HTS) technologies and bioinformatics have drastically changed research in virology, especially for virus discovery. Indeed, proper monitoring of the viral population requires information on the different isolates circulating in the studied area. For this purpose, HTS has greatly facilitated the sequencing of new genomes of detected viruses and their comparison. However, bioinformatics analyses allowing reconstruction of genome sequences and detection of single nucleotide polymorphisms (SNPs) can potentially create bias and has not been widely addressed so far. Therefore, more knowledge is required on the limitations of predicting SNPs based on HTS-generated sequence samples. To address this issue, we compared the ability of 14 plant virology laboratories, each employing a different bioinformatics pipeline, to detect 21 variants of pepino mosaic virus (PepMV) in three samples through large-scale performance testing (PT) using three artificially designed datasets. To evaluate the impact of bioinformatics analyses, they were divided into three key steps: reads pre-processing, virus-isolate identification, and variant calling. Each step was evaluated independently through an original, PT design including discussion and validation between participants at each step. Overall, this work underlines key parameters influencing SNPs detection and proposes recommendations for reliable variant calling for plant viruses. The identification of the closest reference, mapping parameters and manual validation of the detection were recognized as the most impactful analysis steps for the success of the SNPs detections. Strategies to improve the prediction of SNPs are also discussed.

Untargeted-based metabolomics analysis and in vitro/in silico antiviral activity of extracts from Phyllanthus brasiliensis (Aubl.) Poir.

This study describes the molecular profile and the potential antiviral activity of extracts from Phyllanthus brasiliensis, a plant widely found in the Brazilian Amazon. The research aims to shed light on the potential use of this species as a natural antiviral agent. The extracts were analysed using liquid chromatography-mass spectrometry (LC-MS) system, a potent analytical technique to discover drug candidates. In the meantime, in vitro antiviral assays were performed against Mayaro, Oropouche, Chikungunya, and Zika viruses. In addition, the antiviral activity of annotated compounds was predicted by in silico methods. Overall, 44 compounds were annotated in this study. The results revealed that P. brasiliensis has a high content of fatty acids, flavones, flavan-3-ols, and lignans. Furthermore, in vitro assays revealed potent antiviral activity against different arboviruses, especially lignan-rich extracts against Zika virus (ZIKV), as follows: methanolic extract from bark (MEB) [effective concentration for 50% of the cells (EC50 ) = 0.80 μg/mL, selectivity index (SI) = 377.59], methanolic extract from the leaf (MEL) (EC50 = 0.84 μg/mL, SI = 297.62), and hydroalcoholic extract from the leaf (HEL) (EC50 = 1.36 μg/mL, SI = 735.29). These results were supported by interesting in silico prediction, where tuberculatin (a lignan) showed a high antiviral activity score. Phyllanthus brasiliensis extracts contain metabolites that could be a new kick-off point for the discovery of candidates for antiviral drug development, with lignans becoming a promising trend for further virology research.

Rapid and stain-free quantification of viral plaque via lens-free holography and deep learning

A plaque assay—the gold-standard method for measuring the concentration of replication-competent lytic virions—requires staining and usually more than 48 h of runtime. Here we show that lens-free holographic imaging and deep learning can be combined to expedite and automate the assay. The compact imaging device captures phase information label-free at a rate of approximately 0.32 gigapixels per hour per well, covers an area of about 30 × 30 mm2 and a 10-fold larger dynamic range of virus concentration than standard assays, and quantifies the infected area and the number of plaque-forming units. For the vesicular stomatitis virus, the automated plaque assay detected the first cell-lysing events caused by viral replication as early as 5 h after incubation, and in less than 20 h it detected plaque-forming units at rates higher than 90% at 100% specificity. Furthermore, it reduced the incubation time of the herpes simplex virus type 1 by about 48 h and that of the encephalomyocarditis virus by about 20 h. The stain-free assay should be amenable for use in virology research, vaccine development and clinical diagnosis.

Parasitological, Bacteriological and Virological Research of Carp (Cyprinus carpio) in a Case in Hirfanlı Dam Lake in Türkiye

The aim of the present study was shedding light on the disease factors underlying mortality event among common carps inhabiting Hirfanlı Dam Lake in Türkiye in spring of the year 2021. For this purpose various parasitological, bacteriological and virological research techniques were employed. Five parasite genera, Dactylogyrus spp., Myxobolus spp., Eimeria spp., Trichodina spp., Diplostomum spp. were isolated from 13 common carps. The opportunistic bacterial pathogen of fresh water fishes Aeromonas hydrophila was also isolated from wounded fish. No viruses were detected. Fungal infections were encountered in the skin lesions of carps. The source of the encountered morbidity and mortality picture among the studied carps points to the combined action of parasitic, bacterial and fungal agents in these fish. Further investigations on seasonal variations of parasitofauna on the lake are needed for better understanding the dynamics in the ecology of the parasites which are hosted by carps in the Hirfanlı Dam Lake.