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1.
Anal Chem ; 95(25): 9680-9686, 2023 06 27.
Article in English | MEDLINE | ID: covidwho-20244047

ABSTRACT

Genetic tests are highly sensitive, and quantitative methods for diagnosing human viral infections, including COVID-19, are also being used to diagnose plant diseases in various agricultural settings. Conventional genetic tests for plant viruses are mostly based on methods that require purification and amplification of viral genomes from plant samples, which generally take several hours in total, making it difficult to use them in rapid detection at point-of-care testing (POCT). In this study, we developed Direct-SATORI, a rapid and robust genetic test that eliminates the purification and amplification processes of viral genomes by extending the recently developed amplification-free digital RNA detection platform called SATORI, allowing the detection of various plant viral genes in a total of less than 15 min with a limit of detection (LoD) of 98 ∼ copies/µL using tomato viruses as an example. In addition, the platform can simultaneously detect eight plant viruses directly from ∼1 mg of tomato leaves with a sensitivity of 96% and a specificity of 99%. Direct-SATORI can be applied to various infections related to RNA viruses, and its practical use is highly anticipated as a versatile platform for plant disease diagnostics in the future.


Subject(s)
COVID-19 , Plant Viruses , Humans , RNA , Plant Viruses/genetics , Limit of Detection , RNA, Viral/genetics , Sensitivity and Specificity , Nucleic Acid Amplification Techniques/methods , COVID-19 Testing
2.
Viruses ; 15(5)2023 05 07.
Article in English | MEDLINE | ID: covidwho-20242796

ABSTRACT

Avian coronaviruses (ACoV) have been shown to be highly prevalent in wild bird populations. More work on avian coronavirus detection and diversity estimation is needed for the breeding territories of migrating birds, where the high diversity and high prevalence of Orthomyxoviridae and Paramyxoviridae have already been shown in wild birds. In order to detect ACoV RNA, we conducted PCR diagnostics of cloacal swab samples from birds, which we monitored during avian influenza A virus surveillance activities. Samples from two distant Asian regions of Russia (Sakhalin region and Novosibirsk region) were tested. Amplified fragments of the RNA-dependent RNA-polymerase (RdRp) of positive samples were partially sequenced to determine the species of Coronaviridae represented. The study revealed a high presence of ACoV among wild birds in Russia. Moreover, there was a high presence of birds co-infected with avian coronavirus, avian influenza virus, and avian paramyxovirus. We found one case of triple co-infection in a Northern Pintail (Anas acuta). Phylogenetic analysis revealed the circulation of a Gammacoronavirus species. A Deltacoronavirus species was not detected, which supports the data regarding the low prevalence of deltacoronaviruses among surveyed bird species.


Subject(s)
Avulavirus , Gammacoronavirus , Influenza A virus , Influenza in Birds , Animals , Ducks , Gammacoronavirus/genetics , Influenza in Birds/epidemiology , Avulavirus/genetics , Siberia/epidemiology , Phylogeny , Birds , Animals, Wild , Influenza A virus/genetics , RNA
3.
Viruses ; 15(5)2023 05 08.
Article in English | MEDLINE | ID: covidwho-20235357

ABSTRACT

BACKGROUND: Since limited data are available, we aimed to compare the efficacy and durability of dolutegravir and darunavir in advanced naïve patients. METHODS: Retrospective multicenter study including AIDS- or late-presenting (def. CD4 ≤ 200/µL) HIV-infected patients starting dolutegravir or ritonavir/cobicistat-boosted darunavir+2NRTIs. Patients were followed from the date of first-line therapy initiation (baseline, BL) to the discontinuation of darunavir or dolutegravir, or for a maximum of 36 months of follow-up. RESULTS: Overall 308 patients (79.2% males, median age 43 years, 40.3% AIDS-presenters, median CD4 66 cells/µL) were enrolled; 181 (58.8%) and 127 (41.2%) were treated with dolutegravir and darunavir, respectively. Incidence of treatment discontinuation (TD), virological failure (VF, defined as a single HIV-RNA > 1000 cp/mL or two consecutive HIV-RNA > 50 cp/mL after 6 months of therapy or after virological suppression had been achieved), treatment failure (the first of TD or VF), and optimal immunological recovery (defined as CD4 ≥ 500/µL + CD4 ≥ 30% + CD4/CD8 ≥ 1) were 21.9, 5.2, 25.6 and 1.4 per 100 person-years of follow-up, respectively, without significant differences between dolutegravir and darunavir (p > 0.05 for all outcomes). However, a higher estimated probability of TD for central nervous system (CNS) toxicity (at 36 months: 11.7% vs. 0%, p = 0.002) was observed for dolutegravir, whereas darunavir showed a higher probability of TD for simplification (at 36 months: 21.3% vs. 5.7%, p = 0.046). CONCLUSIONS: Dolutegravir and darunavir showed similar efficacy in AIDS- and late-presenting patients. A higher risk of TD due to CNS toxicity was observed with dolutegravir, and a higher probability of treatment simplification with darunavir.


Subject(s)
Acquired Immunodeficiency Syndrome , Anti-HIV Agents , HIV Infections , Male , Humans , Adult , Female , Darunavir/therapeutic use , HIV Infections/drug therapy , Acquired Immunodeficiency Syndrome/drug therapy , Heterocyclic Compounds, 3-Ring/adverse effects , RNA , Anti-HIV Agents/adverse effects , Viral Load
4.
Rheumatology (Oxford) ; 61(10): 3912-3918, 2022 10 06.
Article in English | MEDLINE | ID: covidwho-20242590

ABSTRACT

OBJECTIVES: Patients with inflammatory rheumatic diseases (IRDs) treated with the anti-CD20 mAb rituximab (RTX) have been identified as high-risk for severe COVID-19 outcomes. Additionally, there is increased risk due to reduced humoral immune response, induced by therapeutic B cell depletion. This study sought to quantify humoral response after vaccination against SARS-CoV-2 in patients with IRD treated with RTX. It also sought to elucidate the influence of the time frame between the last RTX dose and the first vaccination, or the status of B cell depletion on antibody titre. METHODS: In this case-control study, patients with IRDs previously treated with RTX were examined for humoral immune response after completing the first series of vaccinations with approved vaccines [BNT162b2 (Biontech/Pfizer), RNA-1273 (Moderna), AZD1222 (AstraZeneca/Oxford), Ad26.COV2.S (Janssen/Johnson & Johnson)]. Antibody levels were quantified using the Euroimmun Anti-SARS-CoV-2 QuantiVac ELISA (EI-S1-IgG-quant). Blood samples were taken just before the next infusion with RTX after the vaccination. The interval between the last RTX infusion and the first vaccination against SARS-CoV-2 and other possible factors influencing the antibody levels were evaluated. RESULTS: A total of 102 patients were included. Of these, 65 (64%) showed a negative antibody level (<24 IU (international unit)/ml) after the vaccination. The comparative univariate analysis of the antibody levels achieved a significant result (P = 0.0008) for the time between the last RTX infusion and first vaccination against SARS-CoV-2. No CD19+ peripheral B-cells could be detected in 73 of the patients (72%). CONCLUSION: The study confirms the negative impact of RTX on antibody level after vaccination against SARS-CoV-2. A clear relationship exists between the antibody titre and the interval between the last RTX infusion and the first vaccination, the number of peripheral B-cells, and immunoglobulin quantity. Improved understanding of the effect of these parameters can help guide synchronization of vaccination in relation to the RTX therapy regimen.


Subject(s)
COVID-19 , Rheumatic Diseases , Ad26COVS1 , BNT162 Vaccine , COVID-19/prevention & control , COVID-19 Vaccines , Case-Control Studies , ChAdOx1 nCoV-19 , Humans , Immunoglobulin G , RNA , Rheumatic Diseases/chemically induced , Rheumatic Diseases/drug therapy , Rituximab/therapeutic use , SARS-CoV-2 , Vaccination
5.
Nan Fang Yi Ke Da Xue Xue Bao ; 43(4): 516-526, 2023 Apr 20.
Article in Chinese | MEDLINE | ID: covidwho-20239030

ABSTRACT

OBJECTIVE: To establish a rapid detection and genotyping method for SARS-CoV-2 Omicron BA.4/5 variants using CRISPPR-Cas12a gene editing technology. METHODS: We combined reverse transcription-polymerase chain reaction (RT-PCR) and CRISPR gene editing technology and designed a specific CRISPPR RNA (crRNA) with suboptimal protospacer adjacent motifs (PAM) for rapid detection and genotyping of SARS- CoV-2 Omicron BA.4/5 variants. The performance of this RT- PCR/ CRISPPR-Cas12a assay was evaluated using 43 clinical samples of patients infected by wild-type SARS-CoV-2 and the Alpha, Beta, Delta, Omicron BA. 1 and BA. 4/5 variants and 20 SARS- CoV- 2-negative clinical samples infected with 11 respiratory pathogens. With Sanger sequencing method as the gold standard, the specificity, sensitivity, concordance (Kappa) and area under the ROC curve (AUC) of RT-PCR/CRISPPR-Cas12a assay were calculated. RESULTS: This assay was capable of rapid and specific detection of SARS- CoV-2 Omicron BA.4/5 variant within 30 min with the lowest detection limit of 10 copies/µL, and no cross-reaction was observed in SARS-CoV-2-negative clinical samples infected with 11 common respiratory pathogens. The two Omicron BA.4/5 specific crRNAs (crRNA-1 and crRNA-2) allowed the assay to accurately distinguish Omicron BA.4/5 from BA.1 sublineage and other major SARS-CoV-2 variants of concern. For detection of SARS-CoV-2 Omicron BA.4/5 variants, the sensitivity of the established assay using crRNA-1 and crRNA-2 was 97.83% and 100% with specificity of 100% and AUC of 0.998 and 1.000, respectively, and their concordance rate with Sanger sequencing method was 92.83% and 96.41%, respectively. CONCLUSION: By combining RT-PCR and CRISPPR-Cas12a gene editing technology, we successfully developed a new method for rapid detection and identification of SARS-CoV-2 Omicron BA.4/5 variants with a high sensitivity, specificity and reproducibility, which allows rapid detection and genotyping of SARS- CoV-2 variants and monitoring of the emerging variants and their dissemination.


Subject(s)
COVID-19 , Humans , CRISPR-Cas Systems , Genotype , Reproducibility of Results , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/genetics , RNA , COVID-19 Testing
6.
Sensors (Basel) ; 23(10)2023 May 09.
Article in English | MEDLINE | ID: covidwho-20237544

ABSTRACT

Rapid, easy-to-use, and low-cost systems for biological sample testing are important for point-of-care diagnostics and various other health applications. The recent pandemic of Coronavirus Disease 2019 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) showed an urgent need to rapidly and accurately identify the genetic material of SARS-CoV-2, an enveloped ribonucleic acid (RNA) virus, in upper respiratory specimens from people. In general, sensitive testing methods require genetic material extraction from the specimen. Unfortunately, current commercially available extraction kits are expensive and involve time-consuming and laborious extraction procedures. To overcome the difficulties associated with common extraction methods, we propose a simple enzymatic assay for the nucleic acid extraction step using heat mediation to improve the polymerase chain reaction (PCR) reaction sensitivity. Our protocol was tested on Human Coronavirus 229E (HCoV-229E) as an example, which comes from the large coronaviridae family of viruses that affect birds, amphibians, and mammals, of which SARS-CoV-2 is a member. The proposed assay was performed using a low-cost, custom-made, real-time PCR system that incorporates thermal cycling and fluorescence detection. It had fully customizable reaction settings to allow versatile biological sample testing for various applications, including point-of-care medical diagnosis, food and water quality testing, and emergency health situations. Our results show that heat-mediated RNA extraction is a viable extraction method when compared to commercial extraction kits. Further, our study showed that extraction has a direct impact on purified laboratory samples of HCoV-229E, but no direct impact on infected human cells. This is clinically relevant, as it allows us to circumvent the extraction step on clinical samples when using PCR.


Subject(s)
COVID-19 , Nucleic Acids , Animals , Humans , Real-Time Polymerase Chain Reaction , RNA , COVID-19/diagnosis , SARS-CoV-2/genetics , Mammals , COVID-19 Testing
7.
Int J Mol Sci ; 24(10)2023 May 19.
Article in English | MEDLINE | ID: covidwho-20235268

ABSTRACT

The central role of RNA molecules in cell biology has been an expanding subject of study since the proposal of the "RNA world" hypothesis 60 years ago [...].


Subject(s)
Gene Regulatory Networks , RNA , RNA/genetics
8.
Nucleic Acids Res ; 51(6): 2529-2573, 2023 04 11.
Article in English | MEDLINE | ID: covidwho-20235160

ABSTRACT

Eighteen nucleic acid therapeutics have been approved for treatment of various diseases in the last 25 years. Their modes of action include antisense oligonucleotides (ASOs), splice-switching oligonucleotides (SSOs), RNA interference (RNAi) and an RNA aptamer against a protein. Among the diseases targeted by this new class of drugs are homozygous familial hypercholesterolemia, spinal muscular atrophy, Duchenne muscular dystrophy, hereditary transthyretin-mediated amyloidosis, familial chylomicronemia syndrome, acute hepatic porphyria, and primary hyperoxaluria. Chemical modification of DNA and RNA was central to making drugs out of oligonucleotides. Oligonucleotide therapeutics brought to market thus far contain just a handful of first- and second-generation modifications, among them 2'-fluoro-RNA, 2'-O-methyl RNA and the phosphorothioates that were introduced over 50 years ago. Two other privileged chemistries are 2'-O-(2-methoxyethyl)-RNA (MOE) and the phosphorodiamidate morpholinos (PMO). Given their importance in imparting oligonucleotides with high target affinity, metabolic stability and favorable pharmacokinetic and -dynamic properties, this article provides a review of these chemistries and their use in nucleic acid therapeutics. Breakthroughs in lipid formulation and GalNAc conjugation of modified oligonucleotides have paved the way to efficient delivery and robust, long-lasting silencing of genes. This review provides an account of the state-of-the-art of targeted oligo delivery to hepatocytes.


Subject(s)
Oligonucleotides, Antisense , Humans , Morpholinos/pharmacology , Muscular Dystrophy, Duchenne/drug therapy , Muscular Dystrophy, Duchenne/genetics , Oligonucleotides, Antisense/chemistry , Oligonucleotides, Antisense/metabolism , Oligonucleotides, Antisense/therapeutic use , RNA/chemistry , RNA Interference
9.
J Appl Lab Med ; 8(4): 726-741, 2023 07 05.
Article in English | MEDLINE | ID: covidwho-20231323

ABSTRACT

BACKGROUND: Throughout the COVID-19 pandemic, veterinary diagnostic laboratories have tested diagnostic samples for SARS-CoV-2 both in animals and over 6 million human samples. An evaluation of the performance of those laboratories is needed using blinded test samples to ensure that laboratories report reliable data to the public. This interlaboratory comparison exercise (ILC3) builds on 2 prior exercises to assess whether veterinary diagnostic laboratories can detect Delta and Omicron variants spiked in canine nasal matrix or viral transport medium. METHODS: The ILC organizer was an independent laboratory that prepared inactivated Delta variant at levels of 25 to 1000 copies per 50 µL of nasal matrix for blinded analysis. Omicron variant at 1000 copies per 50 µL of transport medium was also included. Feline infectious peritonitis virus (FIPV) RNA was used as a confounder for specificity assessment. Fourteen test samples were prepared for each participant. Participants used their routine diagnostic procedures for RNA extraction and real-time reverse transcriptase-PCR. Results were analyzed according to International Organization for Standardization (ISO) 16140-2:2016. RESULTS: Overall, laboratories demonstrated 93% detection for Delta and 97% for Omicron at 1000 copies per 50 µL. Specificity was 97% for blank samples and 100% for blank samples with FIPV. No differences in Cycle Threshold (Ct) values were significant for samples with the same virus levels between N1 and N2 markers, nor between the 2 variants. CONCLUSIONS: The results indicated that all ILC3 participants were able to detect both Delta and Omicron variants. The canine nasal matrix did not significantly affect SARS-CoV-2 detection.


Subject(s)
COVID-19 , SARS-CoV-2 , Cats , Humans , Animals , Dogs , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19/veterinary , Laboratories , Pandemics , RNA , COVID-19 Testing
10.
Environ Int ; 177: 108022, 2023 07.
Article in English | MEDLINE | ID: covidwho-20231002

ABSTRACT

A non-filter virus inactivation unit was developed that can control the irradiation dose of aerosolized viruses by controlling the lighting pattern of a 280 nm deep-UV (DUV)-LED and the air flowrate. In this study, the inactivation properties of aerosolized SARS-CoV-2 were quantitatively evaluated by controlling the irradiation dose to the virus inside the inactivation unit. The RNA concentration of SARS-CoV-2 remained constant when the total irradiation dose of DUV irradiation to the virus exceeded 16.5 mJ/cm2. This observation suggests that RNA damage may occur in regions below the detection threshold of RT-qPCR assay. However, when the total irradiation dose was less than 16.5 mJ/cm2, the RNA concentration monotonically increased with a decreasing LED irradiation dose. However, the nucleocapsid protein concentration of SARS-CoV-2 was not predominantly dependent on the LED irradiation dose. The plaque assay showed that 99.16% of the virus was inactivated at 8.1 mJ/cm2 of irradiation, and no virus was detected at 12.2 mJ/cm2 of irradiation, resulting in a 99.89% virus inactivation rate. Thus, an irradiation dose of 23% of the maximal irradiation capacity of the virus inactivation unit can activate more than 99% of SARS-CoV-2. These findings are expected to enhance versatility in various applications. The downsizing achieved in our study renders the technology apt for installation in narrow spaces, while the enhanced flowrates establish its viability for implementation in larger facilities.


Subject(s)
COVID-19 , Viruses , Humans , SARS-CoV-2 , Disinfection/methods , Ultraviolet Rays , RNA
11.
Genes (Basel) ; 14(4)2023 03 31.
Article in English | MEDLINE | ID: covidwho-2323545

ABSTRACT

Clustered regularly interspaced short palindromic repeats (CRISPR) and their associated proteins (Cas) are promising molecular diagnostic tools for rapidly and precisely elucidating the structure and function of genomes due to their high specificity, programmability, and multi-system compatibility in nucleic acid recognition. Multiple parameters limit the ability of a CRISPR/Cas system to detect DNA or RNA. Consequently, it must be used in conjunction with other nucleic acid amplification techniques or signal detection techniques, and the reaction components and reaction conditions should be modified and optimized to maximize the detection performance of the CRISPR/Cas system against various targets. As the field continues to develop, CRISPR/Cas systems have the potential to become an ultra-sensitive, convenient, and accurate biosensing platform for the detection of specific target sequences. The design of a molecular detection platform employing the CRISPR/Cas system is asserted on three primary strategies: (1) Performance optimization of the CRISPR/Cas system; (2) enhancement of the detection signal and its interpretation; and (3) compatibility with multiple reaction systems. This article focuses on the molecular characteristics and application value of the CRISPR/Cas system and reviews recent research progress and development direction from the perspectives of principle, performance, and method development challenges to provide a theoretical foundation for the development and application of the CRISPR/CAS system in molecular detection technology.


Subject(s)
CRISPR-Cas Systems , DNA , CRISPR-Cas Systems/genetics , RNA , Genome
12.
PLoS Comput Biol ; 19(5): e1011124, 2023 05.
Article in English | MEDLINE | ID: covidwho-2326149

ABSTRACT

Coronaviruses (CoVs) use -1 programmed ribosomal frameshifting stimulated by RNA pseudoknots in the viral genome to control expression of enzymes essential for replication, making CoV pseudoknots a promising target for anti-coronaviral drugs. Bats represent one of the largest reservoirs of CoVs and are the ultimate source of most CoVs infecting humans, including those causing SARS, MERS, and COVID-19. However, the structures of bat-CoV frameshift-stimulatory pseudoknots remain largely unexplored. Here we use a combination of blind structure prediction followed by all-atom molecular dynamics simulations to model the structures of eight pseudoknots that, together with the SARS-CoV-2 pseudoknot, are representative of the range of pseudoknot sequences in bat CoVs. We find that they all share some key qualitative features with the pseudoknot from SARS-CoV-2, notably the presence of conformers with two distinct fold topologies differing in whether or not the 5' end of the RNA is threaded through a junction, and similar conformations for stem 1. However, they differed in the number of helices present, with half sharing the 3-helix architecture of the SARS-CoV-2 pseudoknot but two containing 4 helices and two others only 2. These structure models should be helpful for future work studying bat-CoV pseudoknots as potential therapeutic targets.


Subject(s)
COVID-19 , Chiroptera , Humans , Animals , SARS-CoV-2/genetics , Frameshift Mutation , RNA , Nucleic Acid Conformation , RNA, Viral/genetics , RNA, Viral/chemistry
13.
J Infect Public Health ; 16(7): 1081-1088, 2023 Jul.
Article in English | MEDLINE | ID: covidwho-2314012

ABSTRACT

BACKGROUND: COVID-19 has become a major public health problem after the outbreak caused by SARS-CoV-2 virus. Great efforts to contain COVID-19 transmission have been applied worldwide. In this context, accurate and fast diagnosis is essential. METHODS: In this prospective study, we evaluated the clinical performance of three different RNA-based molecular tests - RT-qPCR (Charité protocol), RT-qPCR (CDC (USA) protocol) and RT-LAMP - and one rapid test for detecting anti-SARS-CoV-2 IgM and IgG antibodies. RESULTS: Our results demonstrate that RT-qPCR using the CDC (USA) protocol is the most accurate diagnostic test among those evaluated, while oro-nasopharyngeal swabs are the most appropriate biological sample. RT-LAMP was the RNA-based molecular test with lowest sensitivity while the serological test presented the lowest sensitivity among all evaluated tests, indicating that the latter test is not a good predictor of disease in the first days after symptoms onset. Additionally, we observed higher viral load in individuals who reported more than 3 symptoms at the baseline. Nevertheless, viral load had not impacted the probability of testing positive for SARS-CoV-2. CONCLUSION: Our data indicates that RT-qPCR using the CDC (USA) protocol in oro-nasopharyngeal swabs samples should be the method of choice to diagnosis COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19 Testing , Prospective Studies , Brazil/epidemiology , Clinical Laboratory Techniques/methods , Health Personnel , RNA , Immunoglobulin G , Immunoglobulin M , Sensitivity and Specificity
14.
J Gen Virol ; 104(5)2023 05.
Article in English | MEDLINE | ID: covidwho-2313977

ABSTRACT

Recombinant Newcastle disease virus (rNDV) strains engineered to express foreign genes from an additional transcription unit (ATU) are considered as candidate live-attenuated vector vaccines for human and veterinary use. Early during the COVID-19 pandemic we and others generated COVID-19 vaccine candidates based on rNDV expressing a partial or complete SARS-CoV-2 spike (S) protein. In our studies, a number of the rNDV constructs did not show high S expression levels in cell culture or seroconversion in immunized hamsters. Sanger sequencing showed the presence of frequent A-to-G transitions characteristic of adenosine deaminase acting on RNA (ADAR). Subsequent whole genome rNDV sequencing revealed that this biased hypermutation was exclusively localized in the ATU expressing the spike gene, and was related to deamination of adenosines in the negative strand viral genome RNA. The biased hypermutation was found both after virus rescue in chicken cell line DF-1 followed by passaging in embryonated chicken eggs, and after direct virus rescue and subsequent passaging in Vero E6 cells. Levels of biased hypermutation were higher in constructs containing codon-optimized as compared to native S gene sequences, suggesting potential association with increased GC content. These data show that deep sequencing of candidate recombinant vector vaccine constructs in different phases of development is of crucial importance in the development of NDV-based vaccines.


Subject(s)
COVID-19 , Newcastle Disease , Viral Vaccines , Animals , Humans , Newcastle disease virus/genetics , COVID-19 Vaccines , Pandemics , SARS-CoV-2/genetics , Chickens , Vaccines, Synthetic , RNA
15.
J Infect Public Health ; 16(7): 1048-1056, 2023 Jul.
Article in English | MEDLINE | ID: covidwho-2313502

ABSTRACT

BACKGROUND: The global research community has made considerable progress in therapeutic and vaccine research during the COVID-19 pandemic. Several therapeutics have been repurposed for the treatment of COVID-19. One such compound is, favipiravir, which was approved for the treatment of influenza viruses, including drug-resistant influenza. Despite the limited information on its molecular activity, clinical trials have attempted to determine the effectiveness of favipiravir in patients with mild to moderate COVID-19. Here, we report the structural and molecular interaction landscape of the macromolecular complex of favipiravir-RTP and SARS-CoV-2 RdRp with the RNA chain. METHODS: Integrative bioinformatics was used to reveal the structural and molecular interaction landscapes of two macromolecular complexes retrieved from RCSB PDB. RESULTS: We analyzed the interactive residues, H-bonds, and interaction interfaces to evaluate the structural and molecular interaction landscapes of the two macromolecular complexes. We found seven and six H-bonds in the first and second interaction landscapes, respectively. The maximum bond length is 3.79 Å. In the hydrophobic interactions, five residues (Asp618, Asp760, Thr687, Asp623, and Val557) were associated with the first complex and two residues (Lys73 and Tyr217) were associated with the second complex. The mobilities, collective motion, and B-factor of the two macromolecular complexes were analyzed. Finally, we developed different models, including trees, clusters, and heat maps of antiviral molecules, to evaluate the therapeutic status of favipiravir as an antiviral drug. CONCLUSIONS: The results revealed the structural and molecular interaction landscape of the binding mode of favipiravir with the nsp7-nsp8-nsp12-RNA SARS-CoV-2 RdRp complex. Our findings can help future researchers in understanding the mechanism underlying viral action and guide the design of nucleotide analogs that mimic favipiravir and exhibit greater potency as antiviral drugs against SARS-CoV-2 and other infectious viruses. Thus, our work can help in preparing for future epidemics and pandemics.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Pandemics , RNA-Dependent RNA Polymerase , RNA , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Antiviral Agents/chemistry
16.
Lett Appl Microbiol ; 76(6)2023 Jun 01.
Article in English | MEDLINE | ID: covidwho-2312963

ABSTRACT

Wastewater Based Epidemiology (WBE) has become an integral part of the public health effort to track the levels of SARS-CoV-2 within communities. Detection of SARS-CoV-2 in wastewater can be challenging due to relatively low levels of virus within the sample. The wastewater matrix is also comprised of commercial and domestically derived contaminants, as well as RNases, all of which can adversely affect RT-qPCR analysis. To improve SARS-CoV-2 detection within wastewater samples we investigated both the effect of template dilution (as a means to reduce RT-qPCR inhibition) and sample stabilisation via addition of DNA/RNA Shield™ and/or RNA Later™ (to prevent RNA degradation via RNases) as a means to improve viral fragment detection. Using both methodologies, a significant improvement in SARS-CoV-2 detection from wastewater samples was observed. No adverse effects of stabilising agent addition on downstream Next-Generation Sequencing workflows were detected.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , Excipients , Wastewater , RNA , RNA, Viral/genetics
17.
Sci Rep ; 13(1): 7426, 2023 05 08.
Article in English | MEDLINE | ID: covidwho-2312407

ABSTRACT

The key to limiting SARS-CoV-2 spread is to identify virus-infected individuals (both symptomatic and asymptomatic) and isolate them from the general population. Hence, routine weekly testing for SARS-CoV-2 in all asymptomatic (capturing both infected and non-infected) individuals is considered critical in situations where a large number of individuals co-congregate such as schools, prisons, aged care facilities and industrial workplaces. Such testing is hampered by operational issues such as cost, test availability, access to healthcare workers and throughput. We developed the SalivaDirect RT-qPCR assay to increase access to SARS-CoV-2 testing via a low-cost, streamlined protocol using self-collected saliva. To expand the single sample testing protocol, we explored multiple extraction-free pooled saliva testing workflows prior to testing with the SalivaDirect RT-qPCR assay. A pool size of five, with or without heat inactivation at 65 °C for 15 min prior to testing resulted in a positive agreement of 98% and 89%, respectively, and an increased Ct value shift of 1.37 and 1.99 as compared to individual testing of the positive clinical saliva specimens. Applying this shift in Ct value to 316 individual, sequentially collected, SARS-CoV-2 positive saliva specimen results reported from six clinical laboratories using the original SalivaDirect assay, 100% of the samples would have been detected (Ct value < 45) had they been tested in the 1:5 pool strategy. The availability of multiple pooled testing workflows for laboratories can increase test turnaround time, permitting results in a more actionable time frame while minimizing testing costs and changes to laboratory operational flow.


Subject(s)
COVID-19 , Humans , Aged , COVID-19/diagnosis , COVID-19 Testing , SARS-CoV-2/genetics , Saliva , RNA , Specimen Handling , RNA, Viral/genetics
18.
J Med Case Rep ; 17(1): 202, 2023 May 05.
Article in English | MEDLINE | ID: covidwho-2312350

ABSTRACT

BACKGROUND: Acute disseminated encephalomyelitis is a well-known, but rare, side effect of some vaccines, or symptom following a febrile illness. CASE: A 69-year-old, otherwise healthy Hispanic male presented with acute fever, confusion, and later progressive weakness after receiving the first dose of the mRNA-1273 (Moderna) severe acute respiratory syndrome coronavirus 2 vaccine. Considering the progressive deterioration of the patient, despite being on multiple immunosuppressive agents, a brain biopsy was obtained, which revealed nonspecific meningoencephalitis. CONCLUSION: In this case, we highlight the need for a regulatory framework to assist clinicians and patients with coverage of treatment for acute disseminated encephalomyelitis. The use of intravenous immunoglobulin in conjunction with glucocorticoids seems to be an effective treatment option.


Subject(s)
COVID-19 , Encephalomyelitis, Acute Disseminated , Encephalomyelitis , Vaccines , Humans , Male , Middle Aged , Aged , Encephalomyelitis, Acute Disseminated/chemically induced , SARS-CoV-2 , Vaccines/adverse effects , Vaccination , Encephalomyelitis/chemically induced , RNA/therapeutic use
19.
Viruses ; 15(3)2023 03 13.
Article in English | MEDLINE | ID: covidwho-2320343

ABSTRACT

Nucleases are ubiquitous hydrolytic enzymes that cleave phosphodiester bond of DNA (DNases), RNA (RNases), or protein-RNA/DNA (phosphodiesterases), within the strand (endonucleases) or from the end (exonucleases) [...].


Subject(s)
Deoxyribonucleases , Endonucleases , Deoxyribonucleases/chemistry , Phosphoric Diester Hydrolases , DNA/chemistry , RNA/chemistry
20.
Sci Total Environ ; 887: 163785, 2023 Aug 20.
Article in English | MEDLINE | ID: covidwho-2311519

ABSTRACT

Wastewater-based epidemiology (WBE) demonstrates an efficient tool to monitor and predict SARS-CoV-2 community distribution. Many countries across the world have adopted the technique, however, most of these studies were conducted for a short duration with a limited sampling size. In this study, long-term reliability and quantification of wastewater SARS-CoV-2 surveillance is reported via analyzing 16,858 samples collected from 453 different locations across the United Arab Emirates (UAE) from May 2020 to June 2022. The collected composite samples were first incubated at 60 °C followed by filtration, concentration, and then RNA extraction using commercially available kits. The extracted RNA was then analyzed by one-step RT-qPCR and RT-ddPCR, and the data was compared to the reported clinical cases. The average positivity rate in the wastewater samples was found to be 60.61 % (8.41-96.77 %), however, the positivity rate obtained from the RT-ddPCR was significantly higher than the RT-qPCR suggesting higher sensitivity of RT-ddPCR. Time-lagged correlation analysis indicated an increase in positive cases in the wastewater samples when the clinical positive cases declined suggesting that wastewater data are highly affected by the unreported asymptomatic, pre-symptomatic and recovering individuals. The weekly SARS-CoV-2 viral count in the wastewater samples are positively correlated with the diagnosed new clinical cases throughout the studied period and the studied locations. Viral count in wastewater peaked approximately one to two weeks prior to the peaks appearing in active clinical cases indicating that wastewater viral concentrations are effective in predicting clinical cases. Overall, this study further confirms the long-term sensitivity and robust approach of WBE to detect trends in SARS-CoV-2 spread and helps contribute to pandemic management.


Subject(s)
COVID-19 , Humans , United Arab Emirates , Reproducibility of Results , SARS-CoV-2 , Wastewater , Wastewater-Based Epidemiological Monitoring , RNA
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