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Marker Gene
In biology, a marker gene may have several meanings. In nuclear biology and molecular biology, a marker gene is a gene used to determine if a nucleic acid sequence has been successfully inserted into an organism's DNA. In particular, there are two sub-types of these marker genes: a selectable marker and a marker for screening. In metagenomics and phylogenetics, a marker gene is an orthologous gene group which can be used to delineate between taxonomic lineages. Selectable marker A selectable marker protects the organism from a ''selective agent'' that would normally kill it or prevent its growth. In a transformation reaction, depending on the transformation efficiency, only one in several million to billion cells may take up DNA. Rather than checking every single cell, scientists use a selective agent to kill all cells that do not contain the foreign DNA, leaving only the desired ones. Antibiotics are the most common selective agents. In bacteria, antibiotics are used almost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biology
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary information encoded in genes, which can be transmitted to future generations. Another major theme is evolution, which explains the unity and diversity of life. Energy processing is also important to life as it allows organisms to move, grow, and reproduce. Finally, all organisms are able to regulate their own internal environments. Biologists are able to study life at multiple levels of organization, from the molecular biology of a cell to the anatomy and physiology of plants and animals, and evolution of populations.Based on definition from: Hence, there are multiple subdisciplines within biology, each defined by the nature of their research questions and the tools that they use. Like other scientists, biologists use the sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Expression
Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, protein or non-coding RNA, and ultimately affect a phenotype, as the final effect. These products are often proteins, but in non-protein-coding genes such as transfer RNA (tRNA) and small nuclear RNA (snRNA), the product is a functional non-coding RNA. Gene expression is summarized in the central dogma of molecular biology first formulated by Francis Crick in 1958, further developed in his 1970 article, and expanded by the subsequent discoveries of reverse transcription and RNA replication. The process of gene expression is used by all known life— eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea), and utilized by viruses—to generate the macromolecular machinery for life. In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomarker
In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. as cited in Biomarkers are used in many scientific fields. Medicine Biomarkers used in the medical field, are a part of a relatively new clinical toolset categorized by their clinical applications. The three main classes are molecular biomarkers, cellular biomarkers or imaging biomarkers. All three types of biomarkers have a clinical role in narrowing or guiding treatment decisions and follow a sub-categorization of being either predictive, prognostic, or diagnostic. Predictive Predictive molecular, cellular, or imaging biomarkers that pass validation can serve as a method of predicting clinical outcomes. Predictive biomarkers are used to help optimize ide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmid
A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; however, plasmids are sometimes present in archaea and eukaryotic organisms. In nature, plasmids often carry genes that benefit the survival of the organism and confer selective advantage such as antibiotic resistance. While chromosomes are large and contain all the essential genetic information for living under normal conditions, plasmids are usually very small and contain only additional genes that may be useful in certain situations or conditions. Artificial plasmids are widely used as vectors in molecular cloning, serving to drive the replication of recombinant DNA sequences within host organisms. In the laboratory, plasmids may be introduced into a cell via transformation. Synthetic plasmids are available for procurement over the int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insert (molecular Biology)
In Molecular biology, an insert is a piece of DNA that is inserted into a larger DNA vector by a recombinant DNA technique, such as ligation or recombination. This allows it to be multiplied, selected, further manipulated or expressed in a host organism. Inserts can range from physical nucleotide additions using a technique system or the addition of artificial structures on a molecule via mutagenic chemicals, such as ethidium bromide or crystals. Inserts into the genome of an organism normally occur due to natural causes. These causes include environmental conditions and intracellular processes. Environmental inserts range from exposure to radioactive radiation such as Ultraviolet, mutagenic chemicals, or DNA viruses. Intracellular inserts can occur through heritable changes in parent cells or errors in DNA replication or DNA repair. Gene insertion techniques can be used for characteristic mutations in an organism for a desired phenotypic gene expression. A gene insert chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-gal
X-gal (also abbreviated BCIG for 5-bromo-4-chloro-3-indolyl-β--galactopyranoside) is an organic compound consisting of galactose linked to a substituted indole. The compound was synthesized by Jerome Horwitz and collaborators in 1964. The formal chemical name is often shortened to less accurate but also less cumbersome phrases such as bromochloroindoxyl galactoside. The X from indoxyl may be the source of the X in the X-gal contraction. X-gal is often used in molecular biology to test for the presence of an enzyme, β-galactosidase, in the place of its usual target, a β-galactoside. It is also used to detect activity of this enzyme in histochemistry and bacteriology. X-gal is one of many indoxyl glycosides and esters that yield insoluble blue compounds similar to indigo dye as a result of enzyme-catalyzed hydrolysis. Uses X-gal is an analog of lactose, and therefore may be hydrolyzed by the β-galactosidase enzyme which cleaves the β-glycosidic bond in -lactose. X-gal, when c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta-galactosidase
β-Galactosidase (EC 3.2.1.23, lactase, beta-gal or β-gal; systematic name β-D-galactoside galactohydrolase), is a glycoside hydrolase enzyme that catalyzes hydrolysis of terminal non-reducing β-D-galactose residues in β-D-galactosides. β-Galactosides include carbohydrates containing galactose where the glycosidic bond lies above the galactose molecule. Substrates of different β-galactosidases include ganglioside GM1, lactosylceramides, lactose, and various glycoproteins. Function β-Galactosidase is an exoglycosidase which hydrolyzes the β-glycosidic bond formed between a galactose and its organic moiety. It may also cleave fucosides and arabinosides but with much lower efficiency. It is an essential enzyme in the human body. Deficiencies in the protein can result in galactosialidosis or Morquio B syndrome. In '' E. coli'', the ''lacZ'' gene is the structural gene for β-galactosidase; which is present as part of the inducible system ''lac'' operon which is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue White Screen
Blue is one of the three primary colours in the RYB colour model (traditional colour theory), as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colours; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective. Blue has been an important colour in art and decoration since ancient times. The semi-precious stone lapis lazuli was used in ancient Egypt for jewellery and ornament and later, in the Renaissance, to make the pigment ultramarine, the most expensive of all pigments. In the ei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
β-glucuronidase
Beta-glucuronidases are members of the glycosidase family of enzymes that catalyze breakdown of complex carbohydrates. Human β-glucuronidase is a type of glucuronidase (a member of glycosidase Family 2) that catalyzes hydrolysis of β-D- glucuronic acid residues from the non-reducing end of mucopolysaccharides (also referred to as glycosaminoglycans) such as heparan sulfate. Human β-glucuronidase is located in the lysosome. In the gut, brush border β-glucuronidase converts conjugated bilirubin to the unconjugated form for reabsorption. Beta-glucuronidase is also present in breast milk, which contributes to neonatal jaundice. The protein is encoded by the ''GUSB'' gene in humans and by the ''uidA'' gene in bacteria. Structure Human β-glucuronidase is synthesized as an 80 kDa monomer (653 amino acids) before proteolysis removes 18 amino acids from the C-terminal end to form a 78 kDa monomer. Beta-glucuronidase exists as a 332 kDa homotetramer. Beta-glucuronidase conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GUS Assay
The GUS reporter system (''GUS'': β-glucuronidase) is a reporter gene system, particularly useful in plant molecular biology and microbiology. Several kinds of GUS reporter gene assay are available, depending on the substrate used. The term GUS staining refers to the most common of these, a histochemical technique. Purpose The purpose of this technique is to analyze the activity of a gene transcription promoter (in terms of expression of a so-called reporter gene under the regulatory control of that promoter) either in a quantitative manner, involving some measure of activity, or qualitatively (on versus off) through visualization of its activity in different cells, tissues, or organs. The technique utilizes the uidA gene of Escherichia coli, which codes for the enzyme, β-glucuronidase; this enzyme, when incubated with specific colorless or non-fluorescent substrates, can convert them into stable colored or fluorescent products. The presence of the GUS-induced color indicates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Green Fluorescent Protein
The green fluorescent protein (GFP) is a protein that exhibits bright green fluorescence when exposed to light in the blue to ultraviolet range. The label ''GFP'' traditionally refers to the protein first isolated from the jellyfish '' Aequorea victoria'' and is sometimes called ''avGFP''. However, GFPs have been found in other organisms including corals, sea anemones, zoanithids, copepods and lancelets. The GFP from ''A. victoria'' has a major excitation peak at a wavelength of 395 nm and a minor one at 475 nm. Its emission peak is at 509 nm, which is in the lower green portion of the visible spectrum. The fluorescence quantum yield (QY) of GFP is 0.79. The GFP from the sea pansy ('' Renilla reniformis'') has a single major excitation peak at 498 nm. GFP makes for an excellent tool in many forms of biology due to its ability to form an internal chromophore without requiring any accessory cofactors, gene products, or enzymes / substrates other than mol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Chemistry
Nuclear chemistry is the sub-field of chemistry dealing with radioactivity, nuclear processes, and transformations in the nuclei of atoms, such as nuclear transmutation and nuclear properties. It is the chemistry of radioactive elements such as the actinides, radium and radon together with the chemistry associated with equipment (such as nuclear reactors) which are designed to perform nuclear processes. This includes the corrosion of surfaces and the behavior under conditions of both normal and abnormal operation (such as during an accident). An important area is the behavior of objects and materials after being placed into a nuclear waste storage or disposal site. It includes the study of the chemical effects resulting from the absorption of radiation within living animals, plants, and other materials. The radiation chemistry controls much of radiation biology as radiation has an effect on living things at the molecular scale. To explain it another way, the radiation alters the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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