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I-motif
i-motif DNA, short for intercalated-motif DNA, are cytosine-rich four-stranded quadruplex DNA structures, similar to the G-quadruplex structures that are formed in guanine-rich regions of DNA. History This structure was first discovered in 1993 by Maurice Guéron at École Polytechnique in Palaiseau, France. It was found when two antiparallel doubled stranded DNA complexes with cytosine-protonated cytosine (C·C*) base pairs became associated with one another. This formed a complex 4- stranded DNA complex. The structure was originally found only ''in vitro'', usually at a slightly acidic pH, but was recently discovered in the nuclei of human cells. A new antibody fragment was created, and was found to have highly specific binding affinity for I-motif complexes, but did not bind to other DNA structures, making it optimal for identifying i-motif structures in cells. During their media release in April 2018, Dr. Mahdi Zeraati and colleagues mentioned that these complexes are consta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G-quadruplex
In molecular biology, G-quadruplex secondary structures (G4) are formed in nucleic acids by sequences that are rich in guanine. They are helical in shape and contain guanine tetrads that can form from one, two or four strands. The unimolecular forms often occur naturally near the ends of the chromosomes, better known as the telomeric regions, and in transcriptional regulatory regions of multiple genes, both in microbes and across vertebrates including oncogenes in humans. Four guanine bases can associate through Hoogsteen hydrogen bonding to form a square planar structure called a guanine tetrad (G-tetrad or G-quartet), and two or more guanine tetrads (from G-tracts, continuous runs of guanine) can stack on top of each other to form a G-quadruplex. The placement and bonding to form G-quadruplexes is not random and serve very unusual functional purposes. The quadruplex structure is further stabilized by the presence of a cation, especially potassium, which sits in a centr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minor Groove
In molecular biology, the term double helix refers to the structure formed by double-stranded molecules of nucleic acids such as DNA. The double helical structure of a nucleic acid complex arises as a consequence of its secondary structure, and is a fundamental component in determining its tertiary structure. The structure was discovered by Rosalind Franklin and her student Raymond Gosling, Maurice Wilkins, James Watson, and Francis Crick, while the term "double helix" entered popular culture with the 1968 publication of Watson's '' The Double Helix: A Personal Account of the Discovery of the Structure of DNA''. The DNA double helix biopolymer of nucleic acid is held together by nucleotides which base pair together. In B-DNA, the most common double helical structure found in nature, the double helix is right-handed with about 10–10.5 base pairs per turn. The double helix structure of DNA contains a ''major groove'' and ''minor groove''. In B-DNA the major groove is wider th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G418
G418 (geneticin) is an aminoglycoside antibiotic similar in structure to gentamicin B1. It is produced by '' Micromonospora rhodorangea''. G418 blocks polypeptide synthesis by inhibiting the elongation step in both prokaryotic and eukaryotic cells. Resistance to G418 is conferred by the neo gene from Tn5 encoding an aminoglycoside 3'-phosphotransferase, APT 3' II. G418 is an analog of neomycin sulfate, and has similar mechanism as neomycin. G418 is commonly used in laboratory research to select genetically engineered cells . In general, for bacteria and algae, concentrations of 5 μg/mL or less are used; for mammalian cells, concentrations of approximately 400 μg/mL are used for selection and 200 μg/mL for maintenance. However, optimal concentration for resistant clones selection in mammalian cells depends on the cell line used as well as on the plasmid carrying the resistance gene. Therefore, antibiotic titration should be done to find the best condition for ever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Regulation
Regulation of gene expression, or gene regulation, includes a wide range of mechanisms that are used by cells to increase or decrease the production of specific gene products (protein or RNA). Sophisticated programs of gene expression are widely observed in biology, for example to trigger developmental pathways, respond to environmental stimuli, or adapt to new food sources. Virtually any step of gene expression can be modulated, from transcriptional initiation, to RNA processing, and to the post-translational modification of a protein. Often, one gene regulator controls another, and so on, in a gene regulatory network. Gene regulation is essential for viruses, prokaryotes and eukaryotes as it increases the versatility and adaptability of an organism by allowing the cell to express protein when needed. Although as early as 1951, Barbara McClintock showed interaction between two genetic loci, Activator (''Ac'') and Dissociator (''Ds''), in the color formation of maize seeds, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In Vivo
Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and plants, as opposed to a tissue extract or dead organism. Examples of investigations ''in vivo'' include: the pathogenesis of disease by comparing the effects of bacterial infection with the effects of purified bacterial toxins; the development of non-antibiotics, antiviral drugs, and new drugs generally; and new surgical procedures. Consequently, animal testing and clinical trials are major elements of ''in vivo'' research. ''In vivo'' testing is often employed over ''in vitro'' because it is better suited for observing the overall effects of an experiment on a living subject. In drug discovery, for example, verification of efficacy ''in vivo'' is crucial, because ''in vitro'' assays can sometimes yield misleading results with drug c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thioflavin
Thioflavins are fluorescent dyes that are available as at least two compounds, namely Thioflavin T and Thioflavin S. Both are used for histology staining and biophysical studies of protein aggregation. In particular, these dyes have been used since 1989 to investigate amyloid formation. They are also used in biophysical studies of the electrophysiology of bacteria. Thioflavins are corrosive, irritant, and acutely toxic, causing serious eye damage. Thioflavin T has been used in research into Alzheimer's disease and other neurodegenerative diseases. Thioflavin T Thioflavin T (Basic Yellow 1, Methylene yellow, CI 49005, or ThT) is a benzothiazole salt obtained by the methylation of dehydrothiotoluidine with methanol in the presence of hydrochloric acid. The dye is widely used to visualize and quantify the presence of misfolded protein aggregates called amyloid, both ''in vitro'' and ''in vivo'' (e.g., plaques composed of amyloid beta found in the brains of Alzheimer's disease pat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Violet
Crystal violet or gentian violet, also known as methyl violet 10B or hexamethyl pararosaniline chloride, is a triphenylmethane, triarylmethane dye used as a histological stain and in Gram staining, Gram's method of classifying bacteria. Crystal violet has antibacterial, Antifungal medication, antifungal, and anthelmintic (Anthelmintic, vermicide) properties and was formerly important as a topical antiseptic. The medical use of the dye has been largely superseded by more modern drugs, although it is still listed by the World Health Organization. The name ''gentian violet'' was originally used for a mixture of methyl pararosaniline dyes (methyl violet), but is now often considered a synonym for ''crystal violet''. The name refers to its colour, being like that of the petals of certain Gentiana, gentian flowers; it is not made from gentians or list of plants known as violet, violets. Production A number of possible routes can be used to prepare crystal violet. The original procedur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitidine
Nitidine is a benzophenanthridine alkaloid found in species of the genus '' Zanthoxylum '', notably in '' Zanthoxylum nitidum''. This compound has an anti-malarial activity.Bouquet, J., et al. (2012)Biological activities of nitidine, a potential anti-malarial lead compound.''Malaria Journal'' 11:67 References Isoquinoline alkaloids Benzodioxoles Quinoline alkaloids Alkaloids found in Rutaceae Antimalarial agents Methoxy compounds Heterocyclic compounds with 5 rings {{alkaloid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graphene Quantum Dot
Graphene quantum dots (GQDs) are graphene nanoparticles with a size less than 100 nm. Due to their exceptional properties such as low toxicity, stable photoluminescence, chemical stability and pronounced quantum confinement effect, GQDs are considered as a novel material for biological, opto-electronics, energy and environmental applications. Properties Graphene quantum dots (GQDs) consist of one or a few layers of graphene and are smaller than 100 nm in size. They are chemically and physically stable, have a large surface to mass ratio and can be dispersed in water easily due to functional groups at the edges. The fluorescence emission of GQDs can extend across a broad spectral range, including the UV, visible, and IR. The origin of GQD fluorescence emission is a subject of debate, as it has been related to quantum confinement effects, defect states and functional groups that might depend on the pH, when GQDs are dispersed in water. Their electronic structure depends s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SWCNT
A carbon nanotube (CNT) is a tube made of carbon with a diameter in the nanometre range (nanoscale). They are one of the allotropes of carbon. Two broad classes of carbon nanotubes are recognized: * ''Single-walled carbon nanotubes'' (''SWCNTs'') have diameters around 0.5–2.0 nanometres, about 100,000 times smaller than the width of a human hair. They can be idealised as cutouts from a two-dimensional graphene sheet rolled up to form a hollow cylinder. * ''Multi-walled carbon nanotubes'' (''MWCNTs'') consist of nested single-wall carbon nanotubes in a nested, tube-in-tube structure. Double- and triple-walled carbon nanotubes are special cases of MWCNT. Carbon nanotubes can exhibit remarkable properties, such as exceptional tensile strength and thermal conductivity because of their nanostructure and strength of the bonds between carbon atoms. Some SWCNT structures exhibit high electrical conductivity while others are semiconductors. In addition, carbon nanotubes can be chem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tobramycin
Tobramycin is an aminoglycoside antibiotic derived from '' Streptomyces tenebrarius'' that is used to treat various types of bacterial infections, particularly Gram-negative infections. It is especially effective against species of ''Pseudomonas''. It was patented in 1965, and approved for medical use in 1974. It is on the World Health Organization's List of Essential Medicines. In 2022, it was the 281st most commonly prescribed medication in the United States, with more than 600,000 prescriptions. Medical uses Tobramycin does not pass the gastro-intestinal tract, so for systemic use it can only be given intravenously or by injection into a muscle. Eye drops and ointments (tobramycin only, Tobrex, or combined with dexamethasone, sold as Tobradex) and nebulised formulations both have low systemic absorption. The formulation for injection is branded Nebcin. The nebulised formulation (brand name Tobi) is indicated in the treatment of exacerbations of chronic infectio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tilorone
Tilorone (trade names Amixin, Lavomax and others) is the first recognized Chemical synthesis, synthetic, small molecular weight compound that is an orally active interferon inducer. It is used as an antiviral drug in some countries which do not require double-blind placebo-controlled studies, including Russia. It is effective against Ebola virus in mice. It shows activity against Eastern equine encephalitis and related viruses. Pharmacology Tilorone activates the production of interferon. See also * Cyclic adenosine-inosine monophosphate References Antiviral drugs Fluorenones Phenol ethers Diethylamino compounds {{antiinfective-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
