|
UK Strain
The Alpha variant (B.1.1.7) was a SARS-CoV-2 variant of concern. It was estimated to be 40–80% more transmissible than the wild-type SARS-CoV-2 (with most estimates occupying the middle to higher end of this range). It was first detected in November 2020 from a sample taken in September in the United Kingdom, and began to spread quickly by mid-December, around the same time as infections surged. This increase is thought to be at least partly because of one or more mutations in the virus' spike protein. The variant was also notable for having more mutations than normally seen. By January 2021, more than half of all genomic sequencing of SARS-CoV-2 was carried out in the UK. This had given rise to questions as to how many other important variants were circulating around the world undetected. On 2 February 2021, Public Health England reported that they had detected " limited number of B.1.1.7 VOC-202012/01 genomes with E484K mutations", which they dubbed Variant of Con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variant Of Concern
The term variant of concern (VOC) for SARS-CoV-2, which causes COVID-19, is a category used for variants of the virus where mutations in their spike protein receptor binding domain (RBD) substantially increase binding affinity (e.g., N501Y) in RBD-hACE2 complex (genetic data), while also being linked to rapid spread in human populations (epidemiological data). Before this, an emerging variant may have been labeled a variant of interest, or in some countries a variant under investigation. During or after fuller assessment as a variant of concern the variant is typically assigned to a lineage in the PANGOLIN nomenclature system and to clades in the Nextstrain and GISAID systems. During the COVID-19 pandemic, the SARS-CoV-2 virus has been observed to mutate, with certain combinations of specific point mutations proving to be more concerning than others. This was principally for reasons of transmissibility and virulence, and also with regard to the possible emergence of escape ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic Assignment Of Named Global Outbreak Lineages
The Phylogenetic Assignment of Named Global Outbreak Lineages (PANGOLIN) is a software tool developed by Dr. Áine O'Toole and members of the Andrew Rambaut laboratory, with an associated web application developed by the Centre for Genomic Pathogen Surveillance in South Cambridgeshire. Its purpose is to implement a dynamic nomenclature (known as the PANGO nomenclature) to classify genetic lineages for SARS-CoV-2, the virus that causes COVID-19. A user with a full genome sequence of a sample of SARS-CoV-2 can use the tool to submit that sequence, which is then compared with other genome sequences, and assigned the most likely lineage (PANGO lineage). Single or multiple runs are possible, and the tool can return further information regarding the known history of the assigned lineage. Additionally, it interfaces with Microreact, to show a time sequence of the location of reports of sequenced samples of the same lineage. This latter feature draws on publicly available genomes obtaine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synonymous Substitution
A synonymous substitution (often called a ''silent'' substitution though they are not always silent) is the evolutionary substitution of one base for another in an exon of a gene coding for a protein, such that the produced amino acid sequence is not modified. This is possible because the genetic code is "degenerate", meaning that some amino acids are coded for by more than one three-base-pair codon; since some of the codons for a given amino acid differ by just one base pair from others coding for the same amino acid, a mutation that replaces the "normal" base by one of the alternatives will result in incorporation of the same amino acid into the growing polypeptide chain when the gene is translated. Synonymous substitutions and mutations affecting noncoding DNA are often considered silent mutations; however, it is not always the case that the mutation is silent. A synonymous mutation can affect transcription, splicing, mRNA transport, and translation, any of which could alte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SARS-CoV-2
Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is a strain of coronavirus that causes COVID-19 (coronavirus disease 2019), the respiratory illness responsible for the ongoing COVID-19 pandemic. The virus previously had a provisional name, 2019 novel coronavirus (2019-nCoV), and has also been called the human coronavirus 2019 (HCoV-19 or hCoV-19). First identified in the city of Wuhan, Hubei, China, the World Health Organization declared the outbreak a public health emergency of international concern on January 30, 2020, and a pandemic on March 11, 2020. SARS‑CoV‑2 is a positive-sense single-stranded RNA virus that is contagious in humans. SARS‑CoV‑2 is a virus of the species ''severe acute respiratory syndrome–related coronavirus'' (SARSr-CoV), related to the SARS-CoV-1 virus that caused the 2002–2004 SARS outbreak. Despite its close relation to SARS-CoV-1, its closest known relatives, with which it forms a sister group, are the derived SARS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication (translesion synthesis). Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics (phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutation is the ultimate source o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronavirus Nucleocapsid Protein
The nucleocapsid (N) protein is a protein that packages the positive-sense RNA genome of coronaviruses to form ribonucleoprotein structures enclosed within the viral capsid. The N protein is the most highly expressed of the four major coronavirus structural proteins. In addition to its interactions with RNA, N forms protein-protein interactions with the coronavirus membrane protein (M) during the process of viral assembly. N also has additional functions in manipulating the cell cycle of the host cell. The N protein is highly immunogenic and antibodies to N are found in patients recovered from SARS and Covid-19. History The coronavirus from Wuhan, China was first identified in January 2020. A patient in the state of Washington was given a diagnosis of coronavirus infection on 20 January. A group of scientists based at the Centers for Disease Control and Prevention in Atlanta, Georgia isolated the virus from nasopharyngeal and oropharyngeal swabs and were able to characterize th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ORF8
ORF8 is a gene that encodes a viral accessory protein, Betacoronavirus NS8 protein, in coronaviruses of the subgenus ''Sarbecovirus''. It is one of the least well conserved and most variable parts of the genome. In some viruses, a deletion splits the region into two smaller open reading frames, called ORF8a and ORF8b - a feature present in many SARS-CoV viral isolates from later in the SARS epidemic, as well as in some bat coronaviruses. For this reason the full-length gene and its protein are sometimes called ORF8ab. The full-length gene, exemplified in SARS-CoV-2, encodes a protein with an immunoglobulin domain of unknown function, possibly involving interactions with the host immune system. It is similar in structure to the ORF7a protein, suggesting it may have originated through gene duplication. Structure ORF8 in SARS-CoV-2 encodes a protein of 121 amino acid residues with an N-terminal signal sequence. ORF8 forms a dimer that is covalently linked by disulfide bonds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ORF1ab
ORF1ab (also ORF1a/b) refers collectively to two open reading frames (ORFs), ORF1a and ORF1b, that are conserved in the genomes of nidoviruses, a group of viruses that includes coronaviruses. The genes express large polyproteins that undergo proteolysis to form several nonstructural proteins with various functions in the viral life cycle, including proteases and the components of the replicase-transcriptase complex (RTC). Together the two ORFs are sometimes referred to as the replicase gene. They are related by a programmed ribosomal frameshift that allows the ribosome to continue translating past the stop codon at the end of ORF1a, in a -1 reading frame. The resulting polyproteins are known as pp1a and pp1ab. Expression ORF1a is the first open reading frame at the 5' end of the genome. Together ORF1ab occupies about two thirds of the genome, with the remaining third at the 3' end encoding the structural proteins and accessory proteins. It is translated from a 5' capped RN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amino Acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha amino acids appear in the genetic code. Amino acids can be classified according to the locations of the core structural functional groups, as Alpha and beta carbon, alpha- , beta- , gamma- or delta- amino acids; other categories relate to Chemical polarity, polarity, ionization, and side chain group type (aliphatic, Open-chain compound, acyclic, aromatic, containing hydroxyl or sulfur, etc.). In the form of proteins, amino acid '' residues'' form the second-largest component (water being the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleotide
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common nutrients by the liver. Nucleotides are composed of three subunit molecules: a nucleobase, a five-carbon sugar (ribose or deoxyribose), and a phosphate group consisting of one to three phosphates. The four nucleobases in DNA are guanine, adenine, cytosine and thymine; in RNA, uracil is used in place of thymine. Nucleotides also play a central role in metabolism at a fundamental, cellular level. They provide chemical energy—in the form of the nucleoside triphosphates, adenosine triphosphate (ATP), guanosine triphosphate (GTP), cytidine triphosphate (CTP) and uridine triphosphate (UTP)—throughout the cell for the many cellular func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
E484K Mutation
There are many variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19). Some are believed, or have been stated, to be of particular importance due to their potential for increased transmissibility, increased virulence, or reduced effectiveness of vaccines against them. These variants contribute to the continuation of the COVID-19 pandemic. only the Omicron variant is designated as a circulating variant of concern by the World Health Organization. Overview The emergence of SARS-CoV-2 may have resulted from recombination events between a bat SARS-like coronavirus and a pangolin coronavirus through cross-species transmission. The earliest available SARS-CoV-2 viral genomes were collected from patients in December 2019, and Chinese researchers compared these early genomes with bat and pangolin coronavirus strains to estimate the ancestral human coronavirus type; the identified ancestral genom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
