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2.
Sci Rep ; 11(1): 24145, 2021 12 17.
Article in English | MEDLINE | ID: covidwho-1585802

ABSTRACT

Recent studies suggest that coronaviruses circulate widely in Southeast Asian bat species and that the progenitors of the SARS-Cov-2 virus could have originated in rhinolophid bats in the region. Our objective was to assess the diversity and circulation patterns of coronavirus in several bat species in Southeast Asia. We undertook monthly live-capture sessions and sampling in Cambodia over 17 months to cover all phases of the annual reproduction cycle of bats and test specifically the association between their age and CoV infection status. We additionally examined current information on the reproductive phenology of Rhinolophus and other bat species presently known to occur in mainland southeast China, Vietnam, Laos and Cambodia. Results from our longitudinal monitoring (573 bats belonging to 8 species) showed an overall proportion of positive PCR tests for CoV of 4.2% (24/573) in cave-dwelling bats from Kampot and 4.75% (22/463) in flying-foxes from Kandal. Phylogenetic analysis showed that the PCR amplicon sequences of CoVs (n = 46) obtained clustered in Alphacoronavirus and Betacoronavirus. Interestingly, Hipposideros larvatus sensu lato harbored viruses from both genera. Our results suggest an association between positive detections of coronaviruses and juvenile and immature bats in Cambodia (OR = 3.24 [1.46-7.76], p = 0.005). Since the limited data presently available from literature review indicates that reproduction is largely synchronized among rhinolophid and hipposiderid bats in our study region, particularly in its more seasonal portions (above 16° N), this may lead to seasonal patterns in CoV circulation. Overall, our study suggests that surveillance of CoV in insectivorous bat species in Southeast Asia, including SARS-CoV-related coronaviruses in rhinolophid bats, could be targeted from June to October for species exhibiting high proportions of juveniles and immatures during these months. It also highlights the need to develop long-term longitudinal surveys of bats and improve our understanding of their ecology in the region, for both biodiversity conservation and public health reasons.


Subject(s)
Alphacoronavirus/genetics , Betacoronavirus/genetics , COVID-19/transmission , Chiroptera/growth & development , SARS-CoV-2/genetics , Alphacoronavirus/classification , Animals , Asia, Southeastern/epidemiology , Betacoronavirus/classification , COVID-19/epidemiology , COVID-19/virology , Cambodia/epidemiology , Chiroptera/classification , Chiroptera/virology , Epidemics/prevention & control , Evolution, Molecular , Genome, Viral/genetics , Geography , Humans , Longitudinal Studies , Male , Phylogeny , SARS-CoV-2/classification , SARS-CoV-2/physiology , Species Specificity
3.
J Virol ; 95(15): e0046321, 2021 07 12.
Article in English | MEDLINE | ID: covidwho-1486505

ABSTRACT

The OC43 coronavirus is a human pathogen that usually causes only the common cold. One of its key enzymes, similar to other coronaviruses, is the 2'-O-RNA methyltransferase (MTase), which is essential for viral RNA stability and expression. Here, we report the crystal structure of the 2'-O-RNA MTase in a complex with the pan-methyltransferase inhibitor sinefungin solved at 2.2-Å resolution. The structure reveals an overall fold consistent with the fold observed in other coronaviral MTases. The major differences are in the conformation of the C terminus of the nsp16 subunit and an additional helix in the N terminus of the nsp10 subunits. The structural analysis also revealed very high conservation of the S-adenosyl methionine (SAM) binding pocket, suggesting that the SAM pocket is a suitable spot for the design of antivirals effective against all human coronaviruses. IMPORTANCE Some coronaviruses are dangerous pathogens, while some cause only common colds. The reasons are not understood, although the spike proteins probably play an important role. However, to understand the coronaviral biology in sufficient detail, we need to compare the key enzymes from different coronaviruses. We solved the crystal structure of 2'-O-RNA methyltransferase of the OC43 coronavirus, a virus that usually causes mild colds. The structure revealed some differences in the overall fold but also revealed that the SAM binding site is conserved, suggesting that development of antivirals against multiple coronaviruses is feasible.


Subject(s)
Betacoronavirus/enzymology , Methyltransferases/chemistry , Viral Proteins/chemistry , Betacoronavirus/genetics , Binding Sites , Crystallography, X-Ray , Methyltransferases/genetics , Protein Conformation, alpha-Helical , Viral Proteins/genetics
4.
Viruses ; 13(10)2021 10 06.
Article in English | MEDLINE | ID: covidwho-1460085

ABSTRACT

According to various estimates, only a small percentage of existing viruses have been discovered, naturally much less being represented in the genomic databases. High-throughput sequencing technologies develop rapidly, empowering large-scale screening of various biological samples for the presence of pathogen-associated nucleotide sequences, but many organisms are yet to be attributed specific loci for identification. This problem particularly impedes viral screening, due to vast heterogeneity in viral genomes. In this paper, we present a new bioinformatic pipeline, VirIdAl, for detecting and identifying viral pathogens in sequencing data. We also demonstrate the utility of the new software by applying it to viral screening of the feces of bats collected in the Moscow region, which revealed a significant variety of viruses associated with bats, insects, plants, and protozoa. The presence of alpha and beta coronavirus reads, including the MERS-like bat virus, deserves a special mention, as it once again indicates that bats are indeed reservoirs for many viral pathogens. In addition, it was shown that alignment-based methods were unable to identify the taxon for a large proportion of reads, and we additionally applied other approaches, showing that they can further reveal the presence of viral agents in sequencing data. However, the incompleteness of viral databases remains a significant problem in the studies of viral diversity, and therefore necessitates the use of combined approaches, including those based on machine learning methods.


Subject(s)
Alphacoronavirus/isolation & purification , Betacoronavirus/isolation & purification , Chiroptera/virology , Genome, Viral/genetics , Metagenome/genetics , Alphacoronavirus/classification , Alphacoronavirus/genetics , Animals , Betacoronavirus/classification , Betacoronavirus/genetics , Chiroptera/genetics , Computational Biology/methods , Feces/virology , High-Throughput Nucleotide Sequencing , Metagenomics/methods , Moscow , Phycodnaviridae/classification , Phycodnaviridae/genetics , Phycodnaviridae/isolation & purification , Sequence Analysis, DNA
7.
Viruses ; 13(10)2021 10 01.
Article in English | MEDLINE | ID: covidwho-1444333

ABSTRACT

Coronaviruses (CoVs) are widespread and highly diversified in wildlife and domestic mammals and can emerge as zoonotic or epizootic pathogens and consequently host shift from these reservoirs, highlighting the importance of veterinary surveillance. All genera can be found in mammals, with α and ß showing the highest frequency and diversification. The aims of this study were to review the literature for features of CoV surveillance in animals, to test widely used molecular protocols, and to identify the most effective one in terms of spectrum and sensitivity. We combined a literature review with analyses in silico and in vitro using viral strains and archive field samples. We found that most protocols defined as pan-coronavirus are strongly biased towards α- and ß-CoVs and show medium-low sensitivity. The best results were observed using our new protocol, showing LoD 100 PFU/mL for SARS-CoV-2, 50 TCID50/mL for CaCoV, 0.39 TCID50/mL for BoCoV, and 9 ± 1 log2 ×10-5 HA for IBV. The protocol successfully confirmed the positivity for a broad range of CoVs in 30/30 field samples. Our study points out that pan-CoV surveillance in mammals could be strongly improved in sensitivity and spectrum and propose the application of a new RT-PCR assay, which is able to detect CoVs from all four genera, with an optimal sensitivity for α-, ß-, and γ-.


Subject(s)
Alphacoronavirus/genetics , Coronavirus Infections/veterinary , Deltacoronavirus/genetics , Gammacoronavirus/genetics , SARS-CoV-2/genetics , Animals , Animals, Wild/virology , Betacoronavirus/genetics , COVID-19/veterinary , Chiroptera/virology , Genome, Viral/genetics , Humans , Livestock/virology , Rodentia/virology
9.
Sci Rep ; 11(1): 18847, 2021 09 22.
Article in English | MEDLINE | ID: covidwho-1434148

ABSTRACT

As the SARS-CoV-2 has spread and the pandemic has dragged on, the virus continued to evolve rapidly resulting in the emergence of new highly transmissible variants that can be of public health concern. The evolutionary mechanisms that drove this rapid diversity are not well understood but neutral evolution should open the first insight. The neutral theory of evolution states that most mutations in the nucleic acid sequences are random and they can be fixed or disappear by purifying selection. Herein, we performed a neutrality test to better understand the selective pressures exerted over SARS-CoV-2 spike protein from homologue proteins of Betacoronavirus, as well as to the spikes from human clinical isolates of the virus. Specifically, Tyr and Asn have higher occurrence rates on the Receptor Binding Domain (RBD) and in the overall sequence of spike proteins of Betacoronavirus, whereas His and Arg have lower occurrence rates. The in vivo evolutionary phenomenon of SARS-CoV-2 shows that Glu, Lys, Phe, and Val have the highest probability of occurrence in the emergent viral particles. Amino acids that have higher occurrence than the expected by the neutral control, are favorable and are fixed in the sequence while the ones that have lower occurrence than expected, influence the stability and/or functionality of the protein. Our results show that most unique mutations either for SARS-CoV-2 or its variants of health concern are under selective pressures, which could be related either to the evasion of the immune system, increasing the virus' fitness or altering protein - protein interactions with host proteins. We explored the consequences of those selected mutations in the structure and protein - protein interaction with the receptor. Altogether all these forces have shaped the spike protein and the continually evolving variants.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Amino Acids/chemistry , Amino Acids/genetics , Angiotensin-Converting Enzyme 2/chemistry , Betacoronavirus/genetics , Evolution, Molecular , Genetic Drift , Glycosylation , Humans , Models, Theoretical , Mutation , Protein Binding/genetics , Spike Glycoprotein, Coronavirus/chemistry
12.
HLA ; 96(3): 277-298, 2020 09.
Article in English | MEDLINE | ID: covidwho-1388402

ABSTRACT

We report detailed peptide-binding affinities between 438 HLA Class I and Class II proteins and complete proteomes of seven pandemic human viruses, including coronaviruses, influenza viruses and HIV-1. We contrast these affinities with HLA allele frequencies across hundreds of human populations worldwide. Statistical modelling shows that peptide-binding affinities classified into four distinct categories depend on the HLA locus but that the type of virus is only a weak predictor, except in the case of HIV-1. Among the strong HLA binders (IC50 ≤ 50), we uncovered 16 alleles (the top ones being A*02:02, B*15:03 and DRB1*01:02) binding more than 1% of peptides derived from all viruses, 9 (top ones including HLA-A*68:01, B*15:25, C*03:02 and DRB1*07:01) binding all viruses except HIV-1, and 15 (top ones A*02:01 and C*14:02) only binding coronaviruses. The frequencies of strongest and weakest HLA peptide binders differ significantly among populations from different geographic regions. In particular, Indigenous peoples of America show both higher frequencies of strongest and lower frequencies of weakest HLA binders. As many HLA proteins are found to be strong binders of peptides derived from distinct viral families, and are hence promiscuous (or generalist), we discuss this result in relation to possible signatures of natural selection on HLA promiscuous alleles due to past pathogenic infections. Our findings are highly relevant for both evolutionary genetics and the development of vaccine therapies. However they should not lead to forget that individual resistance and vulnerability to diseases go beyond the sole HLA allelic affinity and depend on multiple, complex and often unknown biological, environmental and other variables.


Subject(s)
Coronavirus Infections/epidemiology , HIV Infections/epidemiology , HLA Antigens/chemistry , Influenza, Human/epidemiology , Pandemics , Peptides/chemistry , Pneumonia, Viral/epidemiology , Severe Acute Respiratory Syndrome/epidemiology , Viral Proteins/chemistry , Africa/epidemiology , Americas/epidemiology , Amino Acid Sequence , Asia/epidemiology , Australia/epidemiology , Betacoronavirus/genetics , Betacoronavirus/immunology , COVID-19 , Computational Biology , Coronavirus Infections/immunology , Coronavirus Infections/virology , Europe/epidemiology , HIV Infections/immunology , HIV Infections/virology , HIV-1/genetics , HIV-1/immunology , HLA Antigens/classification , HLA Antigens/genetics , HLA Antigens/immunology , Humans , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H3N2 Subtype/genetics , Influenza A Virus, H3N2 Subtype/immunology , Influenza A Virus, H7N9 Subtype/genetics , Influenza A Virus, H7N9 Subtype/immunology , Influenza, Human/immunology , Influenza, Human/virology , Kinetics , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/immunology , Peptides/genetics , Peptides/immunology , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Protein Binding , SARS Virus/genetics , SARS Virus/immunology , SARS-CoV-2 , Severe Acute Respiratory Syndrome/immunology , Severe Acute Respiratory Syndrome/virology , Viral Proteins/genetics , Viral Proteins/immunology
14.
J Pediatric Infect Dis Soc ; 9(5): 636-639, 2020 Nov 10.
Article in English | MEDLINE | ID: covidwho-1387930

ABSTRACT

Little is known about the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the coronavirus disease 2019 (COVID-19) on pregnant mothers and their infants. Moreover, there is no definitive evidence that SARS CoV- 2 can be vertically transmitted from an infected mother to the unborn fetus.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/transmission , Infectious Disease Transmission, Vertical , Placenta/virology , Pneumonia, Viral/transmission , Pregnancy Complications, Infectious , Betacoronavirus/genetics , COVID-19 , Female , Humans , In Situ Hybridization , Infant, Newborn , Nasopharynx/virology , Pandemics , Pregnancy , Retrospective Studies , SARS-CoV-2
17.
Sci Rep ; 10(1): 16824, 2020 10 08.
Article in English | MEDLINE | ID: covidwho-1387453

ABSTRACT

The biological mechanisms involved in SARS-CoV-2 infection are only partially understood. Thus we explored the plasma metabolome of patients infected with SARS-CoV-2 to search for diagnostic and/or prognostic biomarkers and to improve the knowledge of metabolic disturbance in this infection. We analyzed the plasma metabolome of 55 patients infected with SARS-CoV-2 and 45 controls by LC-HRMS at the time of viral diagnosis (D0). We first evaluated the ability to predict the diagnosis from the metabotype at D0 in an independent population. Next, we assessed the feasibility of predicting the disease evolution at the 7th and 15th day. Plasma metabolome allowed us to generate a discriminant multivariate model to predict the diagnosis of SARS-CoV-2 in an independent population (accuracy > 74%, sensitivity, specificity > 75%). We identified the role of the cytosine and tryptophan-nicotinamide pathways in this discrimination. However, metabolomic exploration modestly explained the disease evolution. Here, we present the first metabolomic study in SARS-CoV-2 patients which showed a high reliable prediction of early diagnosis. We have highlighted the role of the tryptophan-nicotinamide pathway clearly linked to inflammatory signals and microbiota, and the involvement of cytosine, previously described as a coordinator of cell metabolism in SARS-CoV-2. These findings could open new therapeutic perspectives as indirect targets.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/epidemiology , Coronavirus Infections/metabolism , Cytosine/blood , Metabolome , Metabolomics/methods , Niacinamide/blood , Pneumonia, Viral/epidemiology , Pneumonia, Viral/metabolism , Tryptophan/blood , Aged , Aged, 80 and over , Biomarkers/blood , COVID-19 , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Early Diagnosis , Female , France/epidemiology , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , Prognosis , Reproducibility of Results , SARS-CoV-2 , Sensitivity and Specificity , Severity of Illness Index
19.
Nat Commun ; 11(1): 5874, 2020 11 18.
Article in English | MEDLINE | ID: covidwho-1387320

ABSTRACT

Non-structural proteins (nsp) constitute the SARS-CoV-2 replication and transcription complex (RTC) to play a pivotal role in the virus life cycle. Here we determine the atomic structure of a SARS-CoV-2 mini RTC, assembled by viral RNA-dependent RNA polymerase (RdRp, nsp12) with a template-primer RNA, nsp7 and nsp8, and two helicase molecules (nsp13-1 and nsp13-2), by cryo-electron microscopy. Two groups of mini RTCs with different conformations of nsp13-1 are identified. In both of them, nsp13-1 stabilizes overall architecture of the mini RTC by contacting with nsp13-2, which anchors the 5'-extension of RNA template, as well as interacting with nsp7-nsp8-nsp12-RNA. Orientation shifts of nsp13-1 results in its variable interactions with other components in two forms of mini RTC. The mutations on nsp13-1:nsp12 and nsp13-1:nsp13-2 interfaces prohibit the enhancement of helicase activity achieved by mini RTCs. These results provide an insight into how helicase couples with polymerase to facilitate its function in virus replication and transcription.


Subject(s)
Betacoronavirus/chemistry , Betacoronavirus/physiology , Virus Replication , Betacoronavirus/genetics , Betacoronavirus/metabolism , Binding Sites , Cryoelectron Microscopy , Humans , Methyltransferases/chemistry , Methyltransferases/genetics , Methyltransferases/metabolism , Models, Molecular , Mutation , Protein Binding , Protein Conformation , RNA Helicases/chemistry , RNA Helicases/genetics , RNA Helicases/metabolism , RNA, Viral/metabolism , SARS-CoV-2 , Structure-Activity Relationship , Transcription, Genetic , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism
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