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Viral Load
Viral load, also known as viral burden, is a numerical expression of the quantity of virus in a given volume of fluid, including biological and environmental specimens. It is not to be confused with viral titre or viral titer, which depends on the assay. When an assay for measuring the infective virus particle is done (Plaque assay, Focus assay), viral titre often refers to the ''concentration'' of infectious viral particles, which is different from the ''total'' viral particles. Viral load is measured using body fluids sputum and blood plasma. As an example of environmental specimens, the viral load of norovirus can be determined from run-off water on garden produce. Norovirus has not only prolonged viral shedding and has the ability to survive in the environment but a minuscule infectious dose is required to produce infection in humans: less than 100 viral particles. Viral load is often expressed as viral particles, (virions) or infectious particles per mL depending on the type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sputum
Sputum is mucus that is coughed up from the lower airways (the trachea and bronchi). In medicine, sputum samples are usually used for a naked-eye examination, microbiological investigation of respiratory infections, and Cytopathology, cytological investigations of respiratory system. A naked eye exam of the sputum can be done at home by a patient in order to note the various colors (see below). Any hint of yellow or green color (pus) suggests an airway infection (but does not indicate the type of organism causing it). Such color hints are best detected when the sputum is viewed against a bright white background, such as white paper, a white pot, or a white sink surface. Having green, yellow, or thickened phlegm (sputum) does not always indicate the presence of an infection. Also, if an infection is present, the color of the phlegm (sputum) does not determine whether a virus, a bacterium or another pathogen has caused it. Simple allergies can also cause changes in the color of mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleic Acid
Nucleic acids are large biomolecules that are crucial in all cells and viruses. They are composed of nucleotides, which are the monomer components: a pentose, 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If the sugar is ribose, the polymer is RNA; if the sugar is deoxyribose, a variant of ribose, the polymer is DNA. Nucleic acids are chemical compounds that are found in nature. They carry information in cells and make up genetic material. These acids are very common in all living things, where they create, encode, and store information in every living cell of every outline of life forms, life-form on Earth. In turn, they send and express that information inside and outside the cell nucleus. From the inner workings of the cell to the young of a living thing, they contain and provide information via the nucleic acid sequence. This gives the RNA and DNA their unmistakable 'la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASBA (molecular Biology)
Nucleic acid sequence-based amplification, commonly referred to as NASBA, is a method in molecular biology which is used to produce multiple copies of single stranded RNA. NASBA is a two-step process that takes RNA and anneals specially designed primers, then utilizes an enzyme cocktail to amplify it. Background Nucleic acid amplification is a technique used to produce several copies of a specific segment of RNA/DNA. Amplified RNA and DNA can be used for a variety of applications, such as genotyping, sequencing, and detection of bacteria or viruses. There are two different types of amplification, non-isothermal and isothermal. Non-isothermal amplification produces multiple copies of RNA/DNA through reiterative cycling between different temperatures. Isothermal amplification produces multiple copies of RNA/DNA at a constant reaction temperature. NASBA takes single stranded RNA, anneals primers to it at 65°C, and then amplifies it at 41°C to produce multiple copies of single strand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Transcriptase
A reverse transcriptase (RT) is an enzyme used to convert RNA genome to DNA, a process termed reverse transcription. Reverse transcriptases are used by viruses such as HIV and hepatitis B to replicate their genomes, by retrotransposon mobile genetic elements to proliferate within the host genome, and by eukaryotic cells to extend the telomeres at the ends of their linear chromosomes. The process does not violate the flows of genetic information as described by the classical central dogma, but rather expands it to include transfers of information from RNA to DNA. Retroviral RT has three sequential biochemical activities: RNA-dependent DNA polymerase activity, ribonuclease H (RNase H), and DNA-dependent DNA polymerase activity. Collectively, these activities enable the enzyme to convert single-stranded RNA into double-stranded cDNA. In retroviruses and retrotransposons, this cDNA can then integrate into the host genome, from which new RNA copies can be made via host-cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Transcription Polymerase Chain Reaction
Reverse transcription polymerase chain reaction (RT-PCR) is a laboratory technique combining reverse transcription of RNA into DNA (in this context called complementary DNA or cDNA) and amplification of specific DNA targets using polymerase chain reaction (PCR). It is primarily used to measure the amount of a specific RNA. This is achieved by monitoring the amplification reaction using fluorescence, a technique called real-time PCR or quantitative PCR (qPCR). Confusion can arise because some authors use the acronym RT-PCR to denote real-time PCR. In this article, RT-PCR will denote Reverse Transcription PCR. Combined RT-PCR and qPCR are routinely used for analysis of gene expression and quantification of viral RNA in research and clinical settings. The close association between RT-PCR and qPCR has led to metonymic use of the term qPCR to mean RT-PCR. Such use may be confusing, as RT-PCR can be used without qPCR, for example to enable molecular cloning, sequencing or simple det ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrase
Retroviral integrase (IN) is an enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ... produced by a retrovirus (such as HIV) that integrates (forms covalent links between) its genetic information into that of the host cell it infects. Retroviral INs are not to be confused with phage integrases ( recombinases) used in biotechnology, such as λ phage integrase, as discussed in site-specific recombination. The macromolecular complex of an IN macromolecule bound to the ends of the viral DNA ends has been referred to as the '' intasome''; IN is a key component in this and the retroviral pre-integration complex. Structure All retroviral IN proteins contain three canonical domains, connected by flexible linkers: * an N-terminal HH-CC zinc-binding domain (a three-heli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleotides
Nucleotides are Organic compound, organic molecules composed of a nitrogenous base, a pentose sugar 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, life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common Nutrient, nutrients by the liver. Nucleotides are composed of three subunit molecules: a nucleobase, a pentose, 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 triph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primer (molecular Biology)
A primer is a short, single-stranded nucleic acid used by all living organisms in the initiation of DNA synthesis. A synthetic primer is a type of oligo, short for oligonucleotide. DNA polymerases (responsible for DNA replication) are only capable of adding nucleotides to the 3’-end of an existing nucleic acid, requiring a primer be bound to the template before DNA polymerase can begin a complementary strand. DNA polymerase adds nucleotides after binding to the RNA primer and synthesizes the whole strand. Later, the RNA strands must be removed accurately and replaced with DNA nucleotides. This forms a gap region known as a nick that is filled in using a ligase. The removal process of the RNA primer requires several enzymes, such as Fen1, Lig1, and others that work in coordination with DNA polymerase, to ensure the removal of the RNA nucleotides and the addition of DNA nucleotides. Living organisms use solely RNA primers, while laboratory techniques in biochemistry and mole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerase
In biochemistry, a polymerase is an enzyme (Enzyme Commission number, EC 2.7.7.6/7/19/48/49) that synthesizes long chains of polymers or nucleic acids. DNA polymerase and RNA polymerase are used to assemble DNA and RNA molecules, respectively, by copying a DNA template strand using Base pair, base-pairing interactions or RNA by half ladder replication. A DNA polymerase from the thermophile, thermophilic bacterium, ''Thermus aquaticus'' (''Taq'') (Protein Data Bank, PDB]1BGX EC 2.7.7.7) is used in the polymerase chain reaction, an important technique of molecular biology. A polymerase may be template-dependent or template-independent. Polynucleotide adenylyltransferase, Poly-A-polymerase is an example of template independent polymerase. Terminal deoxynucleotidyl transferase also known to have template independent and template dependent activities. By function *DNA polymerase (DNA-directed DNA polymerase, DdDP) **Family A: DNA polymerase I; Pol POLG, γ, POLQ, θ, DNA polymer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In Vitro
''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), cells or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology and its subdisciplines are traditionally done in labware such as test tubes, flasks, Petri dishes, and microtiter plates. Studies conducted using components of an organism that have been isolated from their usual biological surroundings permit a more detailed or more convenient analysis than can be done with whole organisms; however, results obtained from ''in vitro'' experiments may not fully or accurately predict the effects on a whole organism. In contrast to ''in vitro'' experiments, ''in vivo'' studies are those conducted in living organisms, including humans, known as clinical trials, and whole plants. Definition ''In vitro'' (Latin language, Latin for "in glass"; often not italicized in English usage) studies are conducted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerase Chain Reaction
The polymerase chain reaction (PCR) is a method widely used to make millions to billions of copies of a specific DNA sample rapidly, allowing scientists to amplify a very small sample of DNA (or a part of it) sufficiently to enable detailed study. PCR was invented in 1983 by American biochemist Kary Mullis at Cetus Corporation. Mullis and biochemist Michael Smith (chemist), Michael Smith, who had developed other essential ways of manipulating DNA, were jointly awarded the Nobel Prize in Chemistry in 1993. PCR is fundamental to many of the procedures used in genetic testing and research, including analysis of Ancient DNA, ancient samples of DNA and identification of infectious agents. Using PCR, copies of very small amounts of DNA sequences are exponentially amplified in a series of cycles of temperature changes. PCR is now a common and often indispensable technique used in medical laboratory research for a broad variety of applications including biomedical research and forensic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CE Marking
The presence of the logo on Product (business), commercial products indicates that the Manufacturing, manufacturer or importer affirms the goods' conformity with European Environment, health and safety, health, safety, and environmental protection Technical standard, standards. It is not a quality indicator or a certification mark. The CE marking is required for goods sold in the European Economic Area (EEA); goods sold elsewhere may also carry the mark. The mark indicates that the product may be traded freely in any part of the European Economic Area, regardless of its country of origin. It consists of the CE logo and, if applicable, the four digit identification number of the notified body involved in the conformity assessment procedure. Meaning The mark on a product indicates that the manufacturer or importer of that product affirms its compliance with the relevant European Union law, EU legislation and the product may be sold anywhere in the European Economic Area (EEA) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
