Nucleotide sequences, generated by iterative rounds of SELEX APTAMER TECHNIQUE, that bind to a target molecule specifically and with high affinity.
Peptide sequences, generated by iterative rounds of SELEX APTAMER TECHNIQUE, that bind to a target molecule specifically and with high affinity.
The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.
Adenine nucleotides are molecules that consist of an adenine base attached to a ribose sugar and one, two, or three phosphate groups, including adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP), which play crucial roles in energy transfer and signaling processes within cells.
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Guanine nucleotides are cyclic or linear molecules that consist of a guanine base, a pentose sugar (ribose in the cyclic form, deoxyribose in the linear form), and one or more phosphate groups, playing crucial roles in signal transduction, protein synthesis, and regulation of enzymatic activities.
Polymers made up of a few (2-20) nucleotides. In molecular genetics, they refer to a short sequence synthesized to match a region where a mutation is known to occur, and then used as a probe (OLIGONUCLEOTIDE PROBES). (Dorland, 28th ed)
A group of ribonucleotides (up to 12) in which the phosphate residues of each ribonucleotide act as bridges in forming diester linkages between the ribose moieties.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Purines attached to a RIBOSE and a phosphate that can polymerize to form DNA and RNA.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
The techniques used to produce molecules exhibiting properties that conform to the demands of the experimenter. These techniques combine methods of generating structural changes with methods of selection. They are also used to examine proposed mechanisms of evolution under in vitro selection conditions.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Any of a variety of procedures which use biomolecular probes to measure the presence or concentration of biological molecules, biological structures, microorganisms, etc., by translating a biochemical interaction at the probe surface into a quantifiable physical signal.
Cyclic nucleotides are closed-chain molecules formed from nucleotides (ATP or GTP) through the action of enzymes called cyclases, functioning as second messengers in various cellular signaling pathways, with cAMP and cGMP being the most prominent members.
Molecules of DNA that possess enzymatic activity.
Protein factors that promote the exchange of GTP for GDP bound to GTP-BINDING PROTEINS.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
A biosensing technique in which biomolecules capable of binding to specific analytes or ligands are first immobilized on one side of a metallic film. Light is then focused on the opposite side of the film to excite the surface plasmons, that is, the oscillations of free electrons propagating along the film's surface. The refractive index of light reflecting off this surface is measured. When the immobilized biomolecules are bound by their ligands, an alteration in surface plasmons on the opposite side of the film is created which is directly proportional to the change in bound, or adsorbed, mass. Binding is measured by changes in the refractive index. The technique is used to study biomolecular interactions, such as antigen-antibody binding.
Pyrimidines with a RIBOSE and phosphate attached that can polymerize to form DNA and RNA.
A large collection of DNA fragments cloned (CLONING, MOLECULAR) from a given organism, tissue, organ, or cell type. It may contain complete genomic sequences (GENOMIC LIBRARY) or complementary DNA sequences, the latter being formed from messenger RNA and lacking intron sequences.
The rate dynamics in chemical or physical systems.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A method for determining points of contact between interacting proteins or binding sites of proteins to nucleic acids. Protein footprinting utilizes a protein cutting reagent or protease. Protein cleavage is inhibited where the proteins, or nucleic acids and protein, contact each other. After completion of the cutting reaction, the remaining peptide fragments are analyzed by electrophoresis.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
A 60-kDa extracellular protein of Streptomyces avidinii with four high-affinity biotin binding sites. Unlike AVIDIN, streptavidin has a near neutral isoelectric point and is free of carbohydrate side chains.
A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.
Ribonucleic acid that makes up the genetic material of viruses.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
The relationships of groups of organisms as reflected by their genetic makeup.
Higher-order DNA and RNA structures formed from guanine-rich sequences. They are formed around a core of at least 2 stacked tetrads of hydrogen-bonded GUANINE bases. They can be formed from one two or four separate strands of DNA (or RNA) and can display a wide variety of topologies, which are a consequence of various combinations of strand direction, length, and sequence. (From Nucleic Acids Res. 2006;34(19):5402-15)
High molecular weight polymers containing a mixture of purine and pyrimidine nucleotides chained together by ribose or deoxyribose linkages.
A technology, in which sets of reactions for solution or solid-phase synthesis, is used to create molecular libraries for analysis of compounds on a large scale.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
The functional hereditary units of BACTERIA.
Inorganic compounds that contain fluorine as an integral part of the molecule.
Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.
Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.
Genotypic differences observed among individuals in a population.
A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal (CODON, TERMINATOR). Most codons are universal, but some organisms do not produce the transfer RNAs (RNA, TRANSFER) complementary to all codons. These codons are referred to as unassigned codons (CODONS, NONSENSE).
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.
Part of a MESSENGER RNA molecule that undergoes a conformation change upon binding a specific metabolite or other small molecule thereby regulating the messenger RNA's transcription, post-transcriptional processing, transport, translation, or stability in response to varying levels of the metabolite or other small molecule.
Established cell cultures that have the potential to propagate indefinitely.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.
A multistage process that includes cloning, physical mapping, subcloning, sequencing, and information analysis of an RNA SEQUENCE.
Pairing of purine and pyrimidine bases by HYDROGEN BONDING in double-stranded DNA or RNA.
A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR).
Deoxyribonucleic acid that makes up the genetic material of viruses.
The use of devices which use detector molecules to detect, investigate, or analyze other molecules, macromolecules, molecular aggregates, or organisms.
RNA that has catalytic activity. The catalytic RNA sequence folds to form a complex surface that can function as an enzyme in reactions with itself and other molecules. It may function even in the absence of protein. There are numerous examples of RNA species that are acted upon by catalytic RNA, however the scope of this enzyme class is not limited to a particular type of substrate.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.
Proteins found in any species of bacterium.
The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.
The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.
A collection of cloned peptides, or chemically synthesized peptides, frequently consisting of all possible combinations of amino acids making up an n-amino acid peptide.
An enzyme formed from PROTHROMBIN that converts FIBRINOGEN to FIBRIN.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
A guanine nucleotide containing one phosphate group esterified to the sugar moiety and found widely in nature.
A group of atoms or molecules attached to other molecules or cellular structures and used in studying the properties of these molecules and structures. Radioactive DNA or RNA sequences are used in MOLECULAR GENETICS to detect the presence of a complementary sequence by NUCLEIC ACID HYBRIDIZATION.
The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.
The processes of RNA tertiary structure formation.
A guanine nucleotide containing two phosphate groups esterified to the sugar moiety.
Adenine nucleotide containing one phosphate group esterified to the sugar moiety in the 2'-, 3'-, or 5'-position.
Phosphate esters of THYMIDINE in N-glycosidic linkage with ribose or deoxyribose, as occurs in nucleic acids. (From Dorland, 28th ed, p1154)
Cytosine nucleotides are organic compounds that consist of a nitrogenous base (cytosine), a pentose sugar (ribose in RNA or deoxyribose in DNA), and at least one phosphate group, playing crucial roles in genetic information storage, transmission, and expression within nucleic acids.
Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)
A family of RNA plant viruses that infect a wide range of herbaceous and woody plant species. There are at least eight genera including POTEXVIRUS and CARLAVIRUS, both of which are highly immunogenic.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
A theoretical representative nucleotide or amino acid sequence in which each nucleotide or amino acid is the one which occurs most frequently at that site in the different sequences which occur in nature. The phrase also refers to an actual sequence which approximates the theoretical consensus. A known CONSERVED SEQUENCE set is represented by a consensus sequence. Commonly observed supersecondary protein structures (AMINO ACID MOTIFS) are often formed by conserved sequences.
The complete genetic complement contained in a DNA or RNA molecule in a virus.
The functional hereditary units of VIRUSES.
Techniques of nucleotide sequence analysis that increase the range, complexity, sensitivity, and accuracy of results by greatly increasing the scale of operations and thus the number of nucleotides, and the number of copies of each nucleotide sequenced. The sequencing may be done by analysis of the synthesis or ligation products, hybridization to preexisting sequences, etc.
DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.
The development and use of techniques to study physical phenomena and construct structures in the nanoscale size range or smaller.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Proteins prepared by recombinant DNA technology.
Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.
The study of fluid channels and chambers of tiny dimensions of tens to hundreds of micrometers and volumes of nanoliters or picoliters. This is of interest in biological MICROCIRCULATION and used in MICROCHEMISTRY and INVESTIGATIVE TECHNIQUES.
A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
Systems for the delivery of drugs to target sites of pharmacological actions. Technologies employed include those concerning drug preparation, route of administration, site targeting, metabolism, and toxicity.
A highly-sensitive (in the picomolar range, which is 10,000-fold more sensitive than conventional electrophoresis) and efficient technique that allows separation of PROTEINS; NUCLEIC ACIDS; and CARBOHYDRATES. (Segen, Dictionary of Modern Medicine, 1992)
Proteins found in any species of virus.
The genetic constitution of individuals with respect to one member of a pair of allelic genes, or sets of genes that are closely linked and tend to be inherited together such as those of the MAJOR HISTOCOMPATIBILITY COMPLEX.
Adenine nucleotides which contain deoxyribose as the sugar moiety.
Uridine 5'-(tetrahydrogen triphosphate). A uracil nucleotide containing three phosphate groups esterified to the sugar moiety.
Any method used for determining the location of and relative distances between genes on a chromosome.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
Methods utilizing the principles of MICROFLUIDICS for sample handling, reagent mixing, and separation and detection of specific components in fluids.
The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.
Macromolecular molds for the synthesis of complementary macromolecules, as in DNA REPLICATION; GENETIC TRANSCRIPTION of DNA to RNA, and GENETIC TRANSLATION of RNA into POLYPEPTIDES.
Sequences of DNA in the genes that are located between the EXONS. They are transcribed along with the exons but are removed from the primary gene transcript by RNA SPLICING to leave mature RNA. Some introns code for separate genes.
Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.
Guanine nucleotides which contain deoxyribose as the sugar moiety.
The sequence at the 5' end of the messenger RNA that does not code for product. This sequence contains the ribosome binding site and other transcription and translation regulating sequences.
The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.

Application of locked nucleic acids to improve aptamer in vivo stability and targeting function. (1/893)

Aptamers are powerful candidates for molecular imaging applications due to a number of attractive features, including rapid blood clearance and tumor penetration. We carried out structure-activity relationship (SAR) studies with the Tenascin-C binding aptamer TTA1, which is a promising candidate for application in tumor imaging with radioisotopes. The aim was to improve its in vivo stability and target binding. We investigated the effect of thermal stabilization of the presumed non-binding double-stranded stem region on binding affinity and resistance against nucleolytic degradation. To achieve maximal thermal stem stabilization melting experiments with model hexanucleotide duplexes consisting of unmodified RNA, 2'-O-methyl RNA (2'-OMe), 2'-Fluoro RNA (2'-F) or Locked Nucleic Acids (LNAs) were initially carried out. Extremely high melting temperatures have been found for an LNA/LNA duplex. TTA1 derivatives with LNA and 2'-OMe modifications within the non-binding stem have subsequently been synthesized. Especially, the LNA-modified TTA1 derivative exhibited significant stem stabilization and markedly improved plasma stability while maintaining its binding affinity to the target. In addition, higher tumor uptake and longer blood retention was found in tumor-bearing nude mice. Thus, our strategy to introduce LNA modifications after the selection procedure is likely to be generally applicable to improve the in vivo stability of aptamers without compromising their binding properties.  (+info)

Optical absorption assay for strand-exchange reactions in unlabeled nucleic acids. (2/893)

The nucleic acid exchange reaction is a common feature for genetic recombination, DNA replication and transcription. Due to the fact that in the strand-exchange reactions the reactant and product molecules have similar or identical nucleotide sequences, the reaction is undetectable. As a rule, the nucleic acids with radioactive or fluorescence labels are used in such studies. Besides the fact that the labels can perturb the reaction and pose a health risk to the investigators, the assays usually involve extra experimental steps: quenching the reaction, separation, visualization and quantification of the products. Here, we describe a straightforward, direct and precise method to study strand-exchange reaction of unlabeled nucleic acids by real-time measurements of optical absorption. The method takes advantage of the property of some guanine-rich oligonucleotides to adopt monomolecular quadruplex conformation in the presence of certain cations. The conformation is characterized by significant absorption in long-wavelength range of the ultraviolet region where usually other secondary structures are transparent. The 'signal' oligonucleotide is incorporated into reactant duplex by annealing with target sequence. Adding the replacement sequence initiates the release of the 'signal' oligonucleotide into solution, which is accompanied by ultraviolet absorption in long-wavelength range.  (+info)

Pegaptanib for neovascular age-related macular degeneration. (3/893)

BACKGROUND: Pegaptanib, an anti-vascular endothelial growth factor therapy, was evaluated in the treatment of neovascular age-related macular degeneration. METHODS: We conducted two concurrent, prospective, randomized, double-blind, multicenter, dose-ranging, controlled clinical trials using broad entry criteria. Intravitreous injection into one eye per patient of pegaptanib (at a dose of 0.3 mg, 1.0 mg, or 3.0 mg) or sham injections were administered every 6 weeks over a period of 48 weeks. The primary end point was the proportion of patients who had lost fewer than 15 letters of visual acuity at 54 weeks. RESULTS: In the combined analysis of the primary end point (for a total of 1186 patients), efficacy was demonstrated, without a dose-response relationship, for all three doses of pegaptanib (P<0.001 for the comparison of 0.3 mg with sham injection; P<0.001 for the comparison of 1.0 mg with sham injection; and P=0.03 for the comparison of 3.0 mg with sham injection). In the group given pegaptanib at 0.3 mg, 70 percent of patients lost fewer than 15 letters of visual acuity, as compared with 55 percent among the controls (P<0.001). The risk of severe loss of visual acuity (loss of 30 letters or more) was reduced from 22 percent in the sham-injection group to 10 percent in the group receiving 0.3 mg of pegaptanib (P<0.001). More patients receiving pegaptanib (0.3 mg), as compared with sham injection, maintained their visual acuity or gained acuity (33 percent vs. 23 percent; P=0.003). As early as six weeks after beginning therapy with the study drug, and at all subsequent points, the mean visual acuity among patients receiving 0.3 mg of pegaptanib was better than in those receiving sham injections (P<0.002). Among the adverse events that occurred, endophthalmitis (in 1.3 percent of patients), traumatic injury to the lens (in 0.7 percent), and retinal detachment (in 0.6 percent) were the most serious and required vigilance. These events were associated with a severe loss of visual acuity in 0.1 percent of patients. CONCLUSIONS: Pegaptanib appears to be an effective therapy for neovascular age-related macular degeneration. Its long-term safety is not known.  (+info)

NMR structures of double loops of an RNA aptamer against mammalian initiation factor 4A. (4/893)

A high affinity RNA aptamer (APT58, 58 nt long) against mammalian initiation factor 4A (eIF4A) requires nearly its entire nucleotide sequence for efficient binding. Since splitting either APT58 or eIF4A into two domains diminishes the affinity for each other, it is suggested that multiple interactions or a global interaction between the two molecules accounts for the high affinity. To understand the structural basis of APT58's global recognition of eIF4A, we determined the solution structure of two essential nucleotide loops (AUCGCA and ACAUAGA) within the aptamer using NMR spectroscopy. The AUCGCA loop is stabilized by a U-turn motif and contains a non-canonical A:A base pair (the single hydrogen bond mismatch: Hoogsteen/Sugar-edge). On the other hand, the ACAUAGA loop is stabilized by an AUA tri-nucleotide loop motif and contains the other type of A:A base pair (single hydrogen bond mismatch: Watson-Crick/Watson-Crick). Considering the known structural and functional properties of APT58, we propose that the AUCGCA loop is directly involved in the interaction with eIF4A, while the flexibility of the ACAUAGA loop is important to support this interaction. The Watson-Crick edges of C7 and C9 in the AUCGCA loop may directly interact with eIF4A.  (+info)

Development of an automated in vitro selection protocol to obtain RNA-based aptamers: identification of a biostable substance P antagonist. (5/893)

We have developed an automated SELEX (Systematic Evolution of Ligands by EXponential Enrichment) process that allows the execution of in vitro selection cycles without any direct manual intervention steps. The automated selection protocol is designed to provide for high flexibility and versatility in terms of choice of buffers and reagents as well as stringency of selection conditions. Employing the automated SELEX process, we have identified RNA aptamers to the mirror-image configuration (d-peptide) of substance P. The peptide substance P belongs to the tachykinin family and exerts various biologically important functions, such as peripheral vasodilation, smooth muscle contraction and pain transmission. The aptamer that was identified most frequently was truncated to the 44mer SUP-A-004. The mirror-image configuration of SUP-A-004, the so-called Spiegelmer, has been shown to bind to naturally occurring l-substance P displaying a K(d) of 40 nM and to inhibit (IC50 of 45 nM) l-substance P-mediated Ca2+ release in a cell culture assay.  (+info)

Proximity extension of circular DNA aptamers with real-time protein detection. (6/893)

Multivalent circular aptamers or 'captamers' have recently been introduced through the merger of aptameric recognition functions with the basic principles of DNA nanotechnology. Aptamers have strong utility as protein-binding motifs for diagnostic applications, where their ease of discovery, thermal stability and low cost make them ideal components for incorporation into targeted protein assays. Here we report upon a property specific to circular DNA aptamers: their intrinsic compatibility with a highly sensitive protein detection method termed the 'proximity extension' assay. The circular DNA architecture facilitates the integration of multiple functional elements into a single molecule: aptameric target recognition, nucleic acid hybridization specificity and rolling circle amplification. Successful exploitation of these properties is demonstrated for the molecular analysis of thrombin, with the assay delivering a detection limit nearly three orders of magnitude below the dissociation constants of the two contributing aptamer-thrombin interactions. Real-time signal amplification and detection under isothermal conditions points towards potential clinical applications, with both fluorescent and bioelectronic methods of detection achieved. This application elaborates the pleiotropic properties of circular DNA aptamers beyond the stability, potency and multitargeting characteristics described earlier.  (+info)

Vertebrate telomere repeat DNAs favor external loop propeller quadruplex structures in the presence of high concentrations of potassium. (7/893)

The circular dichroism, CD, spectra of the telomere repeats of vertebrates, d(TTAGGG), indicate that parallel type quadruplex structures or disordered single-stranded structures are formed in low salt. Anti-parallel quadruplex structures are favored in the presence of high concentrations, 140 mM, of sodium. External loop, also known as propeller, parallel type structures are favored in the presence of high concentrations, 100 mM, of potassium in the presence of either 5 or 140 mM sodium. The cation dependence of the CD spectra of the vertebrate telomere repeat DNAs is distinctly different from that of the telomere repeats of Tetrahymena and Oxytricha as well as that of the thrombin binding aptamer. These results indicate that the external loop structures may be present in vertebrate telomeres under the conditions of high potassium and low sodium concentration found in nuclei.  (+info)

Structural characterization of an anti-gp120 RNA aptamer that neutralizes R5 strains of HIV-1. (8/893)

We recently described the isolation of 2'-fluoropyrimidine-substituted RNA aptamers that bind specifically to the surface glycoprotein (gp 120) of the R5 strain, HIV-1(Ba-L), as presented in a previous study. These aptamers potently neutralize HIV-1 infectivity in human peripheral blood mononuclear cells of both tissue culture lab-adapted strains and diverse R5 clinical isolates from multiple clades. Here, we report a detailed structural characterization of one such neutralizing aptamer, B40, using enzymatic and chemical probing methods. We identify the minimal region of the aptamer essential for binding gp120 and accordingly design a 77-nucleotide truncated aptamer, B40t77. We then quantitatively analyze the binding affinity and neutralization potency of the parental and truncated (minimal) aptamer, and show them to be comparable. Furthermore, using results from secondary structure analysis, RNA mutagenesis and BIAcore surface plasmon resonance (SPR) binding assays, we hypothesize that a folded RNA structure is required to present specific nucleotide sequences to allow gp120-recognition and binding. The information gained from this study may provide leads for development of novel anti-HIV-1 therapies and can be used to extend our understanding of the molecular interactions between the virus and its host cell.  (+info)

Aptamers are short, single-stranded oligonucleotides (DNA or RNA) that bind to specific target molecules with high affinity and specificity. They are generated through an iterative process called Systematic Evolution of Ligands by EXponential enrichment (SELEX), where large libraries of randomized oligonucleotides are subjected to repeated rounds of selection and amplification until sequences with the desired binding properties are identified. Nucleotide aptamers have potential applications in various fields, including diagnostics, therapeutics, and research tools.

The term "nucleotide" refers to the basic building blocks of nucleic acids (DNA and RNA). A nucleotide consists of a pentose sugar (ribose for RNA and deoxyribose for DNA), a phosphate group, and a nitrogenous base. The nitrogenous bases in nucleotides are adenine, guanine, cytosine, thymine (in DNA) or uracil (in RNA). In aptamers, the nucleotide sequences form specific three-dimensional structures that enable them to recognize and bind to their target molecules.

Aptamers are short, single-stranded oligonucleotides (DNA or RNA) or peptides that bind to specific target molecules with high affinity and specificity. They are generated through an iterative process called Systematic Evolution of Ligands by EXponential enrichment (SELEX).

Peptide aptamers, on the other hand, are small protein-like molecules that consist of a short peptide sequence displayed on a scaffold protein. They are generated through molecular display technologies such as phage display or ribosome display. Peptide aptamers can bind to various targets, including proteins, with high affinity and specificity, making them useful tools in basic research and therapeutic applications.

Nucleotides are the basic structural units of nucleic acids, such as DNA and RNA. They consist of a nitrogenous base (adenine, guanine, cytosine, thymine or uracil), a pentose sugar (ribose in RNA and deoxyribose in DNA) and one to three phosphate groups. Nucleotides are linked together by phosphodiester bonds between the sugar of one nucleotide and the phosphate group of another, forming long chains known as polynucleotides. The sequence of these nucleotides determines the genetic information carried in DNA and RNA, which is essential for the functioning, reproduction and survival of all living organisms.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Nucleic acid conformation refers to the three-dimensional structure that nucleic acids (DNA and RNA) adopt as a result of the bonding patterns between the atoms within the molecule. The primary structure of nucleic acids is determined by the sequence of nucleotides, while the conformation is influenced by factors such as the sugar-phosphate backbone, base stacking, and hydrogen bonding.

Two common conformations of DNA are the B-form and the A-form. The B-form is a right-handed helix with a diameter of about 20 Å and a pitch of 34 Å, while the A-form has a smaller diameter (about 18 Å) and a shorter pitch (about 25 Å). RNA typically adopts an A-form conformation.

The conformation of nucleic acids can have significant implications for their function, as it can affect their ability to interact with other molecules such as proteins or drugs. Understanding the conformational properties of nucleic acids is therefore an important area of research in molecular biology and medicine.

Single Nucleotide Polymorphism (SNP) is a type of genetic variation that occurs when a single nucleotide (A, T, C, or G) in the DNA sequence is altered. This alteration must occur in at least 1% of the population to be considered a SNP. These variations can help explain why some people are more susceptible to certain diseases than others and can also influence how an individual responds to certain medications. SNPs can serve as biological markers, helping scientists locate genes that are associated with disease. They can also provide information about an individual's ancestry and ethnic background.

Adenine nucleotides are molecules that consist of a nitrogenous base called adenine, which is linked to a sugar molecule (ribose in the case of adenosine monophosphate or AMP, and deoxyribose in the case of adenosine diphosphate or ADP and adenosine triphosphate or ATP) and one, two, or three phosphate groups. These molecules play a crucial role in energy transfer and metabolism within cells.

AMP contains one phosphate group, while ADP contains two phosphate groups, and ATP contains three phosphate groups. When a phosphate group is removed from ATP, energy is released, which can be used to power various cellular processes such as muscle contraction, nerve impulse transmission, and protein synthesis. The reverse reaction, in which a phosphate group is added back to ADP or AMP to form ATP, requires energy input and often involves the breakdown of nutrients such as glucose or fatty acids.

In addition to their role in energy metabolism, adenine nucleotides also serve as precursors for other important molecules, including DNA and RNA, coenzymes, and signaling molecules.

RNA (Ribonucleic Acid) is a single-stranded, linear polymer of ribonucleotides. It is a nucleic acid present in the cells of all living organisms and some viruses. RNAs play crucial roles in various biological processes such as protein synthesis, gene regulation, and cellular signaling. There are several types of RNA including messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), small nuclear RNA (snRNA), microRNA (miRNA), and long non-coding RNA (lncRNA). These RNAs differ in their structure, function, and location within the cell.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Guanine nucleotides are molecules that play a crucial role in intracellular signaling, cellular regulation, and various biological processes within cells. They consist of a guanine base, a sugar (ribose or deoxyribose), and one or more phosphate groups. The most common guanine nucleotides are GDP (guanosine diphosphate) and GTP (guanosine triphosphate).

GTP is hydrolyzed to GDP and inorganic phosphate by certain enzymes called GTPases, releasing energy that drives various cellular functions such as protein synthesis, signal transduction, vesicle transport, and cell division. On the other hand, GDP can be rephosphorylated back to GTP by nucleotide diphosphate kinases, allowing for the recycling of these molecules within the cell.

In addition to their role in signaling and regulation, guanine nucleotides also serve as building blocks for RNA (ribonucleic acid) synthesis during transcription, where they pair with cytosine nucleotides via hydrogen bonds to form base pairs in the resulting RNA molecule.

Oligonucleotides are short sequences of nucleotides, the building blocks of DNA and RNA. They typically contain fewer than 100 nucleotides, and can be synthesized chemically to have specific sequences. Oligonucleotides are used in a variety of applications in molecular biology, including as probes for detecting specific DNA or RNA sequences, as inhibitors of gene expression, and as components of diagnostic tests and therapies. They can also be used in the study of protein-nucleic acid interactions and in the development of new drugs.

Oligoribonucleotides are short, synthetic chains of ribonucleotides, which are the building blocks of RNA (ribonucleic acid). These chains typically contain fewer than 20 ribonucleotide units, and can be composed of all four types of nucleotides found in RNA: adenine (A), uracil (U), guanine (G), and cytosine (C). They are often used in research for various purposes, such as studying RNA function, regulating gene expression, or serving as potential therapeutic agents.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

Purine nucleotides are fundamental units of life that play crucial roles in various biological processes. A purine nucleotide is a type of nucleotide, which is the basic building block of nucleic acids such as DNA and RNA. Nucleotides consist of a nitrogenous base, a pentose sugar, and at least one phosphate group.

In purine nucleotides, the nitrogenous bases are either adenine (A) or guanine (G). These bases are attached to a five-carbon sugar called ribose in the case of RNA or deoxyribose for DNA. The sugar and base together form the nucleoside, while the addition of one or more phosphate groups creates the nucleotide.

Purine nucleotides have several vital functions within cells:

1. Energy currency: Adenosine triphosphate (ATP) is a purine nucleotide that serves as the primary energy currency in cells, storing and transferring chemical energy for various cellular processes.
2. Genetic material: Both DNA and RNA contain purine nucleotides as essential components of their structures. Adenine pairs with thymine (in DNA) or uracil (in RNA), while guanine pairs with cytosine.
3. Signaling molecules: Purine nucleotides, such as adenosine monophosphate (AMP) and cyclic adenosine monophosphate (cAMP), act as intracellular signaling molecules that regulate various cellular functions, including metabolism, gene expression, and cell growth.
4. Coenzymes: Purine nucleotides can also function as coenzymes, assisting enzymes in catalyzing biochemical reactions. For example, nicotinamide adenine dinucleotide (NAD+) is a purine nucleotide that plays a critical role in redox reactions and energy metabolism.

In summary, purine nucleotides are essential biological molecules involved in various cellular functions, including energy transfer, genetic material formation, intracellular signaling, and enzyme cofactor activity.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Deoxyribonucleic acid (DNA) is the genetic material present in the cells of organisms where it is responsible for the storage and transmission of hereditary information. DNA is a long molecule that consists of two strands coiled together to form a double helix. Each strand is made up of a series of four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - that are linked together by phosphate and sugar groups. The sequence of these bases along the length of the molecule encodes genetic information, with A always pairing with T and C always pairing with G. This base-pairing allows for the replication and transcription of DNA, which are essential processes in the functioning and reproduction of all living organisms.

Sequence homology in nucleic acids refers to the similarity or identity between the nucleotide sequences of two or more DNA or RNA molecules. It is often used as a measure of biological relationship between genes, organisms, or populations. High sequence homology suggests a recent common ancestry or functional constraint, while low sequence homology may indicate a more distant relationship or different functions.

Nucleic acid sequence homology can be determined by various methods such as pairwise alignment, multiple sequence alignment, and statistical analysis. The degree of homology is typically expressed as a percentage of identical or similar nucleotides in a given window of comparison.

It's important to note that the interpretation of sequence homology depends on the biological context and the evolutionary distance between the sequences compared. Therefore, functional and experimental validation is often necessary to confirm the significance of sequence homology.

DNA Sequence Analysis is the systematic determination of the order of nucleotides in a DNA molecule. It is a critical component of modern molecular biology, genetics, and genetic engineering. The process involves determining the exact order of the four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - in a DNA molecule or fragment. This information is used in various applications such as identifying gene mutations, studying evolutionary relationships, developing molecular markers for breeding, and diagnosing genetic diseases.

The process of DNA Sequence Analysis typically involves several steps, including DNA extraction, PCR amplification (if necessary), purification, sequencing reaction, and electrophoresis. The resulting data is then analyzed using specialized software to determine the exact sequence of nucleotides.

In recent years, high-throughput DNA sequencing technologies have revolutionized the field of genomics, enabling the rapid and cost-effective sequencing of entire genomes. This has led to an explosion of genomic data and new insights into the genetic basis of many diseases and traits.

Directed molecular evolution is a laboratory technique used to generate proteins or other molecules with desired properties through an iterative process that mimics natural evolution. This process typically involves the following steps:

1. Generation of a diverse library of variants: A population of molecules is created, usually by introducing random mutations into a parent sequence using techniques such as error-prone PCR or DNA shuffling. The resulting library contains a large number of different sequences, each with potentially unique properties.
2. Screening or selection for desired activity: The library is subjected to a screening or selection process that identifies molecules with the desired activity or property. This could involve an in vitro assay, high-throughput screening, or directed cell sorting.
3. Amplification and reiteration: Molecules that exhibit the desired activity are amplified, either by PCR or through cell growth, and then used as templates for another round of mutagenesis and selection. This process is repeated until the desired level of optimization is achieved.

Directed molecular evolution has been successfully applied to a wide range of molecules, including enzymes, antibodies, and aptamers, enabling the development of improved catalysts, biosensors, and therapeutics.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

Biosensing techniques refer to the methods and technologies used to detect and measure biological molecules or processes, typically through the use of a physical device or sensor. These techniques often involve the conversion of a biological response into an electrical signal that can be measured and analyzed. Examples of biosensing techniques include electrochemical biosensors, optical biosensors, and piezoelectric biosensors.

Electrochemical biosensors measure the electrical current or potential generated by a biochemical reaction at an electrode surface. This type of biosensor typically consists of a biological recognition element, such as an enzyme or antibody, that is immobilized on the electrode surface and interacts with the target analyte to produce an electrical signal.

Optical biosensors measure changes in light intensity or wavelength that occur when a biochemical reaction takes place. This type of biosensor can be based on various optical principles, such as absorbance, fluorescence, or surface plasmon resonance (SPR).

Piezoelectric biosensors measure changes in mass or frequency that occur when a biomolecule binds to the surface of a piezoelectric crystal. This type of biosensor is based on the principle that piezoelectric materials generate an electrical charge when subjected to mechanical stress, and this charge can be used to detect changes in mass or frequency that are proportional to the amount of biomolecule bound to the surface.

Biosensing techniques have a wide range of applications in fields such as medicine, environmental monitoring, food safety, and biodefense. They can be used to detect and measure a variety of biological molecules, including proteins, nucleic acids, hormones, and small molecules, as well as to monitor biological processes such as cell growth or metabolism.

Cyclic nucleotides are formed by the intramolecular phosphoester bond between the phosphate group and the hydroxyl group at the 3'-carbon atom of the ribose sugar in a nucleotide. This creates a cyclic structure, specifically a cyclic phosphate. The most common cyclic nucleotides are cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). These molecules function as second messengers in cells, playing crucial roles in various cellular signaling pathways related to metabolism, gene expression, and cell differentiation. The levels of cAMP and cGMP are tightly regulated by the activities of enzymes such as adenylate cyclase and guanylate cyclase for their synthesis, and phosphodiesterases for their degradation.

Catalytic DNA, also known as deoxyribozyme or DNA enzyme, is a synthetic DNA molecule that has the ability to perform a specific chemical reaction, similar to the function of protein enzymes. These DNA molecules are created in the laboratory through a process called "in vitro selection" or "SELEX" (Systematic Evolution of Ligands by EXponential enrichment), where large populations of random DNA sequences are screened for those that can bind and catalyze a specific chemical reaction.

Once identified, these catalytic DNA molecules can be used for various applications, such as biosensors, gene regulation, and drug delivery. They offer several advantages over traditional protein enzymes, including higher stability under harsh conditions, easier synthesis and modification, and lower immunogenicity. However, their catalytic efficiency is generally lower than that of protein enzymes.

Guanine Nucleotide Exchange Factors (GEFs) are a group of regulatory proteins that play a crucial role in the activation of GTPases, which are enzymes that regulate various cellular processes such as signal transduction, cytoskeleton reorganization, and vesicle trafficking.

GEFs function by promoting the exchange of guanosine diphosphate (GDP) for guanosine triphosphate (GTP) on GTPases. GTP is the active form of the GTPase, and its binding to the GTPase leads to a conformational change that activates the enzyme's function.

In the absence of GEFs, GTPases remain in their inactive GDP-bound state, and cellular signaling pathways are not activated. Therefore, GEFs play a critical role in regulating the activity of GTPases and ensuring proper signal transduction in cells.

There are many different GEFs that are specific to various GTPase families, including Ras, Rho, and Arf families. Dysregulation of GEFs has been implicated in various diseases, including cancer and neurological disorders.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Surface Plasmon Resonance (SPR) is a physical phenomenon that occurs at the interface between a metal and a dielectric material, when electromagnetic radiation (usually light) is shone on it. It involves the collective oscillation of free electrons in the metal, known as surface plasmons, which are excited by the incident light. The resonance condition is met when the momentum and energy of the photons match those of the surface plasmons, leading to a strong absorption of light and an evanescent wave that extends into the dielectric material.

In the context of medical diagnostics and research, SPR is often used as a sensitive and label-free detection technique for biomolecular interactions. By immobilizing one binding partner (e.g., a receptor or antibody) onto the metal surface and flowing the other partner (e.g., a ligand or antigen) over it, changes in the refractive index at the interface can be measured in real-time as the plasmons are disturbed by the presence of bound molecules. This allows for the quantification of binding affinities, kinetics, and specificity with high sensitivity and selectivity.

Pyrimidine nucleotides are organic compounds that play crucial roles in various biological processes, particularly in the field of genetics and molecular biology. They are the building blocks of nucleic acids, which include DNA and RNA, and are essential for the storage, transmission, and expression of genetic information within cells.

Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring. Pyrimidine nucleotides are derivatives of pyrimidine, which contain a phosphate group, a pentose sugar (ribose or deoxyribose), and one of three pyrimidine bases: cytosine (C), thymine (T), or uracil (U).

* Cytosine is present in both DNA and RNA. It pairs with guanine via hydrogen bonding during DNA replication and transcription.
* Thymine is exclusively found in DNA, where it pairs with adenine through two hydrogen bonds.
* Uracil is a pyrimidine base that replaces thymine in RNA molecules and pairs with adenine via two hydrogen bonds during RNA transcription.

Pyrimidine nucleotides, along with purine nucleotides (adenine, guanine, and their derivatives), form the fundamental units of nucleic acids, contributing to the structure, function, and regulation of genetic material in living organisms.

A "gene library" is not a recognized term in medical genetics or molecular biology. However, the closest concept that might be referred to by this term is a "genomic library," which is a collection of DNA clones that represent the entire genetic material of an organism. These libraries are used for various research purposes, such as identifying and studying specific genes or gene functions.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Adenosine Triphosphate (ATP) is a high-energy molecule that stores and transports energy within cells. It is the main source of energy for most cellular processes, including muscle contraction, nerve impulse transmission, and protein synthesis. ATP is composed of a base (adenine), a sugar (ribose), and three phosphate groups. The bonds between these phosphate groups contain a significant amount of energy, which can be released when the bond between the second and third phosphate group is broken, resulting in the formation of adenosine diphosphate (ADP) and inorganic phosphate. This process is known as hydrolysis and can be catalyzed by various enzymes to drive a wide range of cellular functions. ATP can also be regenerated from ADP through various metabolic pathways, such as oxidative phosphorylation or substrate-level phosphorylation, allowing for the continuous supply of energy to cells.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Protein footprinting is a group of techniques used in structural biology to investigate the interactions between proteins and other molecules, such as DNA, RNA, or other proteins. These methods provide information about the spatial arrangement of atoms within a protein or protein complex, as well as details about the binding site and the nature of the interaction with another molecule.

In protein footprinting, the protein of interest is treated with a reagent that modifies specific amino acid residues in a way that can be detected and quantified. The reagents used for protein footprinting can be chemical or enzymatic, and they often target specific side chains or backbone atoms. Examples of such reagents include hydroxyl radicals, which modify the side chains of exposed amino acids; or proteases, which cleave the protein backbone at specific sequences.

The key to protein footprinting is that the presence of another molecule (e.g., DNA, RNA, or protein) can shield certain residues from modification by the reagent. By comparing the pattern of modifications in the presence and absence of the binding partner, researchers can infer which residues are in close proximity to the binding site and thus obtain information about the protein-protein or protein-nucleic acid interface.

Protein footprinting techniques include hydroxyl radical footprinting, chemical modification footprinting, enzymatic footprinting, and crosslinking mass spectrometry. These methods can be used to study various aspects of protein structure and function, such as protein folding, protein-protein interactions, protein-nucleic acid interactions, and post-translational modifications.

DNA primers are short single-stranded DNA molecules that serve as a starting point for DNA synthesis. They are typically used in laboratory techniques such as the polymerase chain reaction (PCR) and DNA sequencing. The primer binds to a complementary sequence on the DNA template through base pairing, providing a free 3'-hydroxyl group for the DNA polymerase enzyme to add nucleotides and synthesize a new strand of DNA. This allows for specific and targeted amplification or analysis of a particular region of interest within a larger DNA molecule.

Streptavidin is not a medical term per se, but rather a biochemical term used in the field of medicine and laboratory research. Streptavidin is a protein that is derived from the bacterium Streptomyces avidinii. It has a unique ability to bind very strongly and specifically to another molecule called biotin, with an association constant that is one of the strongest non-covalent interactions known in nature.

This property makes streptavidin a valuable tool in various medical and research applications such as immunoassays, histology, molecular biology, and drug delivery systems. For example, biotinylated molecules (such as antibodies, DNA, or enzymes) can be linked to streptavidin for detection, purification, or targeting purposes.

In summary, streptavidin is a bacterial protein that binds strongly and specifically to biotin, which is used in various medical and research applications as a tool for detection, purification, or targeting purposes.

Single-stranded DNA (ssDNA) is a form of DNA that consists of a single polynucleotide chain. In contrast, double-stranded DNA (dsDNA) consists of two complementary polynucleotide chains that are held together by hydrogen bonds.

In the double-helix structure of dsDNA, each nucleotide base on one strand pairs with a specific base on the other strand through hydrogen bonding: adenine (A) with thymine (T), and guanine (G) with cytosine (C). This base pairing provides stability to the double-stranded structure.

Single-stranded DNA, on the other hand, lacks this complementary base pairing and is therefore less stable than dsDNA. However, ssDNA can still form secondary structures through intrastrand base pairing, such as hairpin loops or cruciform structures.

Single-stranded DNA is found in various biological contexts, including viral genomes, transcription bubbles during gene expression, and in certain types of genetic recombination. It also plays a critical role in some laboratory techniques, such as polymerase chain reaction (PCR) and DNA sequencing.

A viral RNA (ribonucleic acid) is the genetic material found in certain types of viruses, as opposed to viruses that contain DNA (deoxyribonucleic acid). These viruses are known as RNA viruses. The RNA can be single-stranded or double-stranded and can exist as several different forms, such as positive-sense, negative-sense, or ambisense RNA. Upon infecting a host cell, the viral RNA uses the host's cellular machinery to translate the genetic information into proteins, leading to the production of new virus particles and the continuation of the viral life cycle. Examples of human diseases caused by RNA viruses include influenza, COVID-19 (SARS-CoV-2), hepatitis C, and polio.

Genetic transcription is the process by which the information in a strand of DNA is used to create a complementary RNA molecule. This process is the first step in gene expression, where the genetic code in DNA is converted into a form that can be used to produce proteins or functional RNAs.

During transcription, an enzyme called RNA polymerase binds to the DNA template strand and reads the sequence of nucleotide bases. As it moves along the template, it adds complementary RNA nucleotides to the growing RNA chain, creating a single-stranded RNA molecule that is complementary to the DNA template strand. Once transcription is complete, the RNA molecule may undergo further processing before it can be translated into protein or perform its functional role in the cell.

Transcription can be either "constitutive" or "regulated." Constitutive transcription occurs at a relatively constant rate and produces essential proteins that are required for basic cellular functions. Regulated transcription, on the other hand, is subject to control by various intracellular and extracellular signals, allowing cells to respond to changing environmental conditions or developmental cues.

A ligand, in the context of biochemistry and medicine, is a molecule that binds to a specific site on a protein or a larger biomolecule, such as an enzyme or a receptor. This binding interaction can modify the function or activity of the target protein, either activating it or inhibiting it. Ligands can be small molecules, like hormones or neurotransmitters, or larger structures, like antibodies. The study of ligand-protein interactions is crucial for understanding cellular processes and developing drugs, as many therapeutic compounds function by binding to specific targets within the body.

Polymerase Chain Reaction (PCR) is a laboratory technique used to amplify specific regions of DNA. It enables the production of thousands to millions of copies of a particular DNA sequence in a rapid and efficient manner, making it an essential tool in various fields such as molecular biology, medical diagnostics, forensic science, and research.

The PCR process involves repeated cycles of heating and cooling to separate the DNA strands, allow primers (short sequences of single-stranded DNA) to attach to the target regions, and extend these primers using an enzyme called Taq polymerase, resulting in the exponential amplification of the desired DNA segment.

In a medical context, PCR is often used for detecting and quantifying specific pathogens (viruses, bacteria, fungi, or parasites) in clinical samples, identifying genetic mutations or polymorphisms associated with diseases, monitoring disease progression, and evaluating treatment effectiveness.

Phylogeny is the evolutionary history and relationship among biological entities, such as species or genes, based on their shared characteristics. In other words, it refers to the branching pattern of evolution that shows how various organisms have descended from a common ancestor over time. Phylogenetic analysis involves constructing a tree-like diagram called a phylogenetic tree, which depicts the inferred evolutionary relationships among organisms or genes based on molecular sequence data or other types of characters. This information is crucial for understanding the diversity and distribution of life on Earth, as well as for studying the emergence and spread of diseases.

G-Quadruplexes are higher-order DNA or RNA structures that can form in guanine-rich sequences through the stacking of multiple G-tetrads, which are planar arrangements of four guanine bases held together by Hoogsteen hydrogen bonds. These structures are stabilized by monovalent cations, such as potassium, and can play a role in various cellular processes, including transcription, translation, and genome stability. They have been studied as potential targets for the development of new therapeutic strategies in cancer and other diseases.

Nucleic acids are biological macromolecules composed of linear chains of nucleotides. They play crucial roles in the structure and function of cells, serving as the primary information-carrying molecules in all known forms of life. The two main types of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA is responsible for storing genetic information in a stable form that can be passed down from generation to generation, while RNA plays a key role in translating the genetic code stored in DNA into functional proteins.

Each nucleotide consists of a sugar molecule, a phosphate group, and a nitrogenous base. The sugar in DNA is deoxyribose, while in RNA it is ribose. The nitrogenous bases found in both DNA and RNA include adenine (A), guanine (G), and cytosine (C). Thymine (T) is found in DNA, but uracil (U) takes its place in RNA. These nucleotides are linked together by phosphodiester bonds between the sugar of one nucleotide and the phosphate group of another, forming a long, helical structure with backbones made up of alternating sugar and phosphate groups.

The sequence of these nitrogenous bases along the nucleic acid chain encodes genetic information in the form of codons, which are sets of three consecutive bases that specify particular amino acids or signals for protein synthesis. This information is used to direct the synthesis of proteins through a process called transcription (converting DNA to RNA) and translation (converting RNA to protein).

In summary, nucleic acids are essential biomolecules composed of chains of nucleotides that store, transmit, and express genetic information in cells. They consist of two main types: DNA and RNA, which differ in their sugar type, nitrogenous bases, and functions.

Combinatorial chemistry techniques are a group of methods used in the field of chemistry to synthesize and optimize large libraries of chemical compounds in a rapid and efficient manner. These techniques involve the systematic combination of different building blocks, or reagents, in various arrangements to generate a diverse array of molecules. This approach allows chemists to quickly explore a wide chemical space and identify potential lead compounds for drug discovery, materials science, and other applications.

There are several common combinatorial chemistry techniques, including:

1. **Split-Pool Synthesis:** In this method, a large collection of starting materials is divided into smaller groups, and each group undergoes a series of chemical reactions with different reagents. The resulting products from each group are then pooled together and redistributed for additional rounds of reactions. This process creates a vast number of unique compounds through the iterative combination of building blocks.
2. **Parallel Synthesis:** In parallel synthesis, multiple reactions are carried out simultaneously in separate reaction vessels. Each vessel contains a distinct set of starting materials and reagents, allowing for the efficient generation of a series of related compounds. This method is particularly useful when exploring structure-activity relationships (SAR) or optimizing lead compounds.
3. **Encoded Libraries:** To facilitate the rapid identification of active compounds within large libraries, encoded library techniques incorporate unique tags or barcodes into each molecule. These tags allow for the simultaneous synthesis and screening of compounds, as the identity of an active compound can be determined by decoding its corresponding tag.
4. **DNA-Encoded Libraries (DELs):** DELs are a specific type of encoded library that uses DNA molecules to encode and track chemical compounds. In this approach, each unique compound is linked to a distinct DNA sequence, enabling the rapid identification of active compounds through DNA sequencing techniques.
5. **Solid-Phase Synthesis:** This technique involves the attachment of starting materials to a solid support, such as beads or resins, allowing for the stepwise addition of reagents and building blocks. The solid support facilitates easy separation, purification, and screening of compounds, making it an ideal method for combinatorial chemistry applications.

Combinatorial chemistry techniques have revolutionized drug discovery and development by enabling the rapid synthesis, screening, and optimization of large libraries of chemical compounds. These methods continue to play a crucial role in modern medicinal chemistry and materials science research.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

A plasmid is a small, circular, double-stranded DNA molecule that is separate from the chromosomal DNA of a bacterium or other organism. Plasmids are typically not essential for the survival of the organism, but they can confer beneficial traits such as antibiotic resistance or the ability to degrade certain types of pollutants.

Plasmids are capable of replicating independently of the chromosomal DNA and can be transferred between bacteria through a process called conjugation. They often contain genes that provide resistance to antibiotics, heavy metals, and other environmental stressors. Plasmids have also been engineered for use in molecular biology as cloning vectors, allowing scientists to replicate and manipulate specific DNA sequences.

Plasmids are important tools in genetic engineering and biotechnology because they can be easily manipulated and transferred between organisms. They have been used to produce vaccines, diagnostic tests, and genetically modified organisms (GMOs) for various applications, including agriculture, medicine, and industry.

A gene is a specific sequence of nucleotides in DNA that carries genetic information. Genes are the fundamental units of heredity and are responsible for the development and function of all living organisms. They code for proteins or RNA molecules, which carry out various functions within cells and are essential for the structure, function, and regulation of the body's tissues and organs.

Each gene has a specific location on a chromosome, and each person inherits two copies of every gene, one from each parent. Variations in the sequence of nucleotides in a gene can lead to differences in traits between individuals, including physical characteristics, susceptibility to disease, and responses to environmental factors.

Medical genetics is the study of genes and their role in health and disease. It involves understanding how genes contribute to the development and progression of various medical conditions, as well as identifying genetic risk factors and developing strategies for prevention, diagnosis, and treatment.

In genetics, sequence alignment is the process of arranging two or more DNA, RNA, or protein sequences to identify regions of similarity or homology between them. This is often done using computational methods to compare the nucleotide or amino acid sequences and identify matching patterns, which can provide insight into evolutionary relationships, functional domains, or potential genetic disorders. The alignment process typically involves adjusting gaps and mismatches in the sequences to maximize the similarity between them, resulting in an aligned sequence that can be visually represented and analyzed.

A bacterial gene is a segment of DNA (or RNA in some viruses) that contains the genetic information necessary for the synthesis of a functional bacterial protein or RNA molecule. These genes are responsible for encoding various characteristics and functions of bacteria such as metabolism, reproduction, and resistance to antibiotics. They can be transmitted between bacteria through horizontal gene transfer mechanisms like conjugation, transformation, and transduction. Bacterial genes are often organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule.

It's important to note that the term "bacterial gene" is used to describe genetic elements found in bacteria, but not all genetic elements in bacteria are considered genes. For example, some DNA sequences may not encode functional products and are therefore not considered genes. Additionally, some bacterial genes may be plasmid-borne or phage-borne, rather than being located on the bacterial chromosome.

Fluorine compounds are chemical substances that contain fluorine, the most electronegative and reactive of all elements, as an integral part of their molecular structure. Fluorine is a member of the halogen group in the periodic table and readily forms compounds with many other elements.

Fluoride is the most common form of fluorine compound found in nature, existing as an ion (F-) in minerals such as fluorspar (calcium fluoride, CaF2) and cryolite (sodium aluminum fluoride, Na3AlF6). Fluoride ions can replace hydroxyl ions (OH-) in the crystal structure of tooth enamel, making it more resistant to acid attack by bacteria, which is why fluoride is often added to drinking water and dental products.

Other examples of fluorine compounds include chlorofluorocarbons (CFCs), hydrofluoric acid (HF), sulfur hexafluoride (SF6), and uranium hexafluoride (UF6). Fluorine compounds have a wide range of applications, including use as refrigerants, solvents, pharmaceuticals, and materials for the semiconductor industry. However, some fluorine compounds can be highly toxic or reactive, so they must be handled with care.

Adenosine diphosphate (ADP) is a chemical compound that plays a crucial role in energy transfer within cells. It is a nucleotide, which consists of a adenosine molecule (a sugar molecule called ribose attached to a nitrogenous base called adenine) and two phosphate groups.

In the cell, ADP functions as an intermediate in the conversion of energy from one form to another. When a high-energy phosphate bond in ADP is broken, energy is released and ADP is converted to adenosine triphosphate (ATP), which serves as the main energy currency of the cell. Conversely, when ATP donates a phosphate group to another molecule, it is converted back to ADP, releasing energy for the cell to use.

ADP also plays a role in blood clotting and other physiological processes. In the coagulation cascade, ADP released from damaged red blood cells can help activate platelets and initiate the formation of a blood clot.

DNA restriction enzymes, also known as restriction endonucleases, are a type of enzyme that cut double-stranded DNA at specific recognition sites. These enzymes are produced by bacteria and archaea as a defense mechanism against foreign DNA, such as that found in bacteriophages (viruses that infect bacteria).

Restriction enzymes recognize specific sequences of nucleotides (the building blocks of DNA) and cleave the phosphodiester bonds between them. The recognition sites for these enzymes are usually palindromic, meaning that the sequence reads the same in both directions when facing the opposite strands of DNA.

Restriction enzymes are widely used in molecular biology research for various applications such as genetic engineering, genome mapping, and DNA fingerprinting. They allow scientists to cut DNA at specific sites, creating precise fragments that can be manipulated and analyzed. The use of restriction enzymes has been instrumental in the development of recombinant DNA technology and the Human Genome Project.

Genetic variation refers to the differences in DNA sequences among individuals and populations. These variations can result from mutations, genetic recombination, or gene flow between populations. Genetic variation is essential for evolution by providing the raw material upon which natural selection acts. It can occur within a single gene, between different genes, or at larger scales, such as differences in the number of chromosomes or entire sets of chromosomes. The study of genetic variation is crucial in understanding the genetic basis of diseases and traits, as well as the evolutionary history and relationships among species.

A codon is a sequence of three adjacent nucleotides in DNA or RNA that specifies the insertion of a particular amino acid during protein synthesis, or signals the beginning or end of translation. In DNA, these triplets are read during transcription to produce a complementary mRNA molecule, which is then translated into a polypeptide chain during translation. There are 64 possible codons in the standard genetic code, with 61 encoding for specific amino acids and three serving as stop codons that signal the termination of protein synthesis.

Substrate specificity in the context of medical biochemistry and enzymology refers to the ability of an enzyme to selectively bind and catalyze a chemical reaction with a particular substrate (or a group of similar substrates) while discriminating against other molecules that are not substrates. This specificity arises from the three-dimensional structure of the enzyme, which has evolved to match the shape, charge distribution, and functional groups of its physiological substrate(s).

Substrate specificity is a fundamental property of enzymes that enables them to carry out highly selective chemical transformations in the complex cellular environment. The active site of an enzyme, where the catalysis takes place, has a unique conformation that complements the shape and charge distribution of its substrate(s). This ensures efficient recognition, binding, and conversion of the substrate into the desired product while minimizing unwanted side reactions with other molecules.

Substrate specificity can be categorized as:

1. Absolute specificity: An enzyme that can only act on a single substrate or a very narrow group of structurally related substrates, showing no activity towards any other molecule.
2. Group specificity: An enzyme that prefers to act on a particular functional group or class of compounds but can still accommodate minor structural variations within the substrate.
3. Broad or promiscuous specificity: An enzyme that can act on a wide range of structurally diverse substrates, albeit with varying catalytic efficiencies.

Understanding substrate specificity is crucial for elucidating enzymatic mechanisms, designing drugs that target specific enzymes or pathways, and developing biotechnological applications that rely on the controlled manipulation of enzyme activities.

Restriction mapping is a technique used in molecular biology to identify the location and arrangement of specific restriction endonuclease recognition sites within a DNA molecule. Restriction endonucleases are enzymes that cut double-stranded DNA at specific sequences, producing fragments of various lengths. By digesting the DNA with different combinations of these enzymes and analyzing the resulting fragment sizes through techniques such as agarose gel electrophoresis, researchers can generate a restriction map - a visual representation of the locations and distances between recognition sites on the DNA molecule. This information is crucial for various applications, including cloning, genome analysis, and genetic engineering.

A riboswitch is a region of mRNA that binds to specific small molecules, often metabolites, leading to changes in the structure of the RNA that ultimately regulate gene expression. This binding can either activate or repress transcription or translation of the mRNA, depending on the type of riboswitch and the location of the switch within the mRNA.

Riboswitches are typically found in the 5' untranslated region (5' UTR) of bacterial messenger RNAs and are involved in the regulation of various cellular processes, such as metabolism, stress response, and virulence. They function as genetic switches that allow bacteria to rapidly respond to changes in their environment by modulating gene expression in a way that is specific to the needs of the organism.

Riboswitches are important targets for the development of new antibiotics and other therapeutic agents, as they offer a unique opportunity to selectively inhibit bacterial gene expression without affecting the host organism.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

Genotype, in genetics, refers to the complete heritable genetic makeup of an individual organism, including all of its genes. It is the set of instructions contained in an organism's DNA for the development and function of that organism. The genotype is the basis for an individual's inherited traits, and it can be contrasted with an individual's phenotype, which refers to the observable physical or biochemical characteristics of an organism that result from the expression of its genes in combination with environmental influences.

It is important to note that an individual's genotype is not necessarily identical to their genetic sequence. Some genes have multiple forms called alleles, and an individual may inherit different alleles for a given gene from each parent. The combination of alleles that an individual inherits for a particular gene is known as their genotype for that gene.

Understanding an individual's genotype can provide important information about their susceptibility to certain diseases, their response to drugs and other treatments, and their risk of passing on inherited genetic disorders to their offspring.

Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.

Guanosine triphosphate (GTP) is a nucleotide that plays a crucial role in various cellular processes, such as protein synthesis, signal transduction, and regulation of enzymatic activities. It serves as an energy currency, similar to adenosine triphosphate (ATP), and undergoes hydrolysis to guanosine diphosphate (GDP) or guanosine monophosphate (GMP) to release energy required for these processes. GTP is also a precursor for the synthesis of other essential molecules, including RNA and certain signaling proteins. Additionally, it acts as a molecular switch in many intracellular signaling pathways by binding and activating specific GTPase proteins.

RNA Sequence Analysis is a branch of bioinformatics that involves the determination and analysis of the nucleotide sequence of Ribonucleic Acid (RNA) molecules. This process includes identifying and characterizing the individual RNA molecules, determining their functions, and studying their evolutionary relationships.

RNA Sequence Analysis typically involves the use of high-throughput sequencing technologies to generate large datasets of RNA sequences, which are then analyzed using computational methods. The analysis may include comparing the sequences to reference databases to identify known RNA molecules or discovering new ones, identifying patterns and features in the sequences, such as motifs or domains, and predicting the secondary and tertiary structures of the RNA molecules.

RNA Sequence Analysis has many applications in basic research, including understanding gene regulation, identifying novel non-coding RNAs, and studying evolutionary relationships between organisms. It also has practical applications in clinical settings, such as diagnosing and monitoring diseases, developing new therapies, and personalized medicine.

Base pairing is a specific type of chemical bonding that occurs between complementary base pairs in the nucleic acid molecules DNA and RNA. In DNA, these bases are adenine (A), thymine (T), guanine (G), and cytosine (C). Adenine always pairs with thymine via two hydrogen bonds, while guanine always pairs with cytosine via three hydrogen bonds. This precise base pairing is crucial for the stability of the double helix structure of DNA and for the accurate replication and transcription of genetic information. In RNA, uracil (U) takes the place of thymine and pairs with adenine.

An open reading frame (ORF) is a continuous stretch of DNA or RNA sequence that has the potential to be translated into a protein. It begins with a start codon (usually "ATG" in DNA, which corresponds to "AUG" in RNA) and ends with a stop codon ("TAA", "TAG", or "TGA" in DNA; "UAA", "UAG", or "UGA" in RNA). The sequence between these two points is called a coding sequence (CDS), which, when transcribed into mRNA and translated into amino acids, forms a polypeptide chain.

In eukaryotic cells, ORFs can be located in either protein-coding genes or non-coding regions of the genome. In prokaryotic cells, multiple ORFs may be present on a single strand of DNA, often organized into operons that are transcribed together as a single mRNA molecule.

It's important to note that not all ORFs necessarily represent functional proteins; some may be pseudogenes or result from errors in genome annotation. Therefore, additional experimental evidence is typically required to confirm the expression and functionality of a given ORF.

Viral DNA refers to the genetic material present in viruses that consist of DNA as their core component. Deoxyribonucleic acid (DNA) is one of the two types of nucleic acids that are responsible for storing and transmitting genetic information in living organisms. Viruses are infectious agents much smaller than bacteria that can only replicate inside the cells of other organisms, called hosts.

Viral DNA can be double-stranded (dsDNA) or single-stranded (ssDNA), depending on the type of virus. Double-stranded DNA viruses have a genome made up of two complementary strands of DNA, while single-stranded DNA viruses contain only one strand of DNA.

Examples of dsDNA viruses include Adenoviruses, Herpesviruses, and Poxviruses, while ssDNA viruses include Parvoviruses and Circoviruses. Viral DNA plays a crucial role in the replication cycle of the virus, encoding for various proteins necessary for its multiplication and survival within the host cell.

Molecular probe techniques are analytical methods used in molecular biology and medicine to detect, analyze, and visualize specific biological molecules or cellular structures within cells, tissues, or bodily fluids. These techniques typically involve the use of labeled probes that bind selectively to target molecules, allowing for their detection and quantification.

A molecular probe is a small molecule or biomacromolecule (such as DNA, RNA, peptide, or antibody) that has been tagged with a detectable label, such as a fluorescent dye, radioisotope, enzyme, or magnetic particle. The probe is designed to recognize and bind to a specific target molecule, such as a gene, protein, or metabolite, through complementary base pairing, antigen-antibody interactions, or other forms of molecular recognition.

Molecular probe techniques can be broadly classified into two categories:

1. In situ hybridization (ISH): This technique involves the use of labeled DNA or RNA probes to detect specific nucleic acid sequences within cells or tissues. The probes are designed to complement the target sequence and, upon hybridization, allow for the visualization of the location and quantity of the target molecule using various detection methods, such as fluorescence microscopy, brightfield microscopy, or radioisotopic imaging.
2. Immunohistochemistry (IHC) and immunofluorescence (IF): These techniques utilize antibodies as probes to detect specific proteins within cells or tissues. Primary antibodies are raised against a target protein and, upon binding, can be detected using various methods, such as enzyme-linked secondary antibodies, fluorescent dyes, or gold nanoparticles. IHC is typically used for brightfield microscopy, while IF is used for fluorescence microscopy.

Molecular probe techniques have numerous applications in basic research, diagnostics, and therapeutics, including gene expression analysis, protein localization, disease diagnosis, drug development, and targeted therapy.

A catalytic RNA, often referred to as a ribozyme, is a type of RNA molecule that has the ability to act as an enzyme and catalyze chemical reactions. These RNA molecules contain specific sequences and structures that allow them to bind to other molecules and accelerate chemical reactions without being consumed in the process.

Ribozymes play important roles in various biological processes, such as RNA splicing, translation regulation, and gene expression. One of the most well-known ribozymes is the self-splicing intron found in certain RNA molecules, which can excise itself from the host RNA and then ligase the flanking exons together.

The discovery of catalytic RNAs challenged the central dogma of molecular biology, which held that proteins were solely responsible for carrying out biological catalysis. The finding that RNA could also function as an enzyme opened up new avenues of research and expanded our understanding of the complexity and versatility of biological systems.

Bacterial DNA refers to the genetic material found in bacteria. It is composed of a double-stranded helix containing four nucleotide bases - adenine (A), thymine (T), guanine (G), and cytosine (C) - that are linked together by phosphodiester bonds. The sequence of these bases in the DNA molecule carries the genetic information necessary for the growth, development, and reproduction of bacteria.

Bacterial DNA is circular in most bacterial species, although some have linear chromosomes. In addition to the main chromosome, many bacteria also contain small circular pieces of DNA called plasmids that can carry additional genes and provide resistance to antibiotics or other environmental stressors.

Unlike eukaryotic cells, which have their DNA enclosed within a nucleus, bacterial DNA is present in the cytoplasm of the cell, where it is in direct contact with the cell's metabolic machinery. This allows for rapid gene expression and regulation in response to changing environmental conditions.

Oligodeoxyribonucleotides (ODNs) are relatively short, synthetic single-stranded DNA molecules. They typically contain 15 to 30 nucleotides, but can range from 2 to several hundred nucleotides in length. ODNs are often used as tools in molecular biology research for various applications such as:

1. Nucleic acid detection and quantification (e.g., real-time PCR)
2. Gene regulation (antisense, RNA interference)
3. Gene editing (CRISPR-Cas systems)
4. Vaccine development
5. Diagnostic purposes

Due to their specificity and affinity towards complementary DNA or RNA sequences, ODNs can be designed to target a particular gene or sequence of interest. This makes them valuable tools in understanding gene function, regulation, and interaction with other molecules within the cell.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

Protein biosynthesis is the process by which cells generate new proteins. It involves two major steps: transcription and translation. Transcription is the process of creating a complementary RNA copy of a sequence of DNA. This RNA copy, or messenger RNA (mRNA), carries the genetic information to the site of protein synthesis, the ribosome. During translation, the mRNA is read by transfer RNA (tRNA) molecules, which bring specific amino acids to the ribosome based on the sequence of nucleotides in the mRNA. The ribosome then links these amino acids together in the correct order to form a polypeptide chain, which may then fold into a functional protein. Protein biosynthesis is essential for the growth and maintenance of all living organisms.

"Competitive binding" is a term used in pharmacology and biochemistry to describe the behavior of two or more molecules (ligands) competing for the same binding site on a target protein or receptor. In this context, "binding" refers to the physical interaction between a ligand and its target.

When a ligand binds to a receptor, it can alter the receptor's function, either activating or inhibiting it. If multiple ligands compete for the same binding site, they will compete to bind to the receptor. The ability of each ligand to bind to the receptor is influenced by its affinity for the receptor, which is a measure of how strongly and specifically the ligand binds to the receptor.

In competitive binding, if one ligand is present in high concentrations, it can prevent other ligands with lower affinity from binding to the receptor. This is because the higher-affinity ligand will have a greater probability of occupying the binding site and blocking access to the other ligands. The competition between ligands can be described mathematically using equations such as the Langmuir isotherm, which describes the relationship between the concentration of ligand and the fraction of receptors that are occupied by the ligand.

Competitive binding is an important concept in drug development, as it can be used to predict how different drugs will interact with their targets and how they may affect each other's activity. By understanding the competitive binding properties of a drug, researchers can optimize its dosage and delivery to maximize its therapeutic effect while minimizing unwanted side effects.

A peptide library is a collection of a large number of peptides, which are short chains of amino acids. Each peptide in the library is typically composed of a defined length and sequence, and may contain a variety of different amino acids. Peptide libraries can be synthesized using automated techniques and are often used in scientific research to identify potential ligands (molecules that bind to specific targets) or to study the interactions between peptides and other molecules.

In a peptide library, each peptide is usually attached to a solid support, such as a resin bead, and the entire library can be created using split-and-pool synthesis techniques. This allows for the rapid and efficient synthesis of a large number of unique peptides, which can then be screened for specific activities or properties.

Peptide libraries are used in various fields such as drug discovery, proteomics, and molecular biology to identify potential therapeutic targets, understand protein-protein interactions, and develop new diagnostic tools.

Thrombin is a serine protease enzyme that plays a crucial role in the coagulation cascade, which is a complex series of biochemical reactions that leads to the formation of a blood clot (thrombus) to prevent excessive bleeding during an injury. Thrombin is formed from its precursor protein, prothrombin, through a process called activation, which involves cleavage by another enzyme called factor Xa.

Once activated, thrombin converts fibrinogen, a soluble plasma protein, into fibrin, an insoluble protein that forms the structural framework of a blood clot. Thrombin also activates other components of the coagulation cascade, such as factor XIII, which crosslinks and stabilizes the fibrin network, and platelets, which contribute to the formation and growth of the clot.

Thrombin has several regulatory mechanisms that control its activity, including feedback inhibition by antithrombin III, a plasma protein that inactivates thrombin and other serine proteases, and tissue factor pathway inhibitor (TFPI), which inhibits the activation of factor Xa, thereby preventing further thrombin formation.

Overall, thrombin is an essential enzyme in hemostasis, the process that maintains the balance between bleeding and clotting in the body. However, excessive or uncontrolled thrombin activity can lead to pathological conditions such as thrombosis, atherosclerosis, and disseminated intravascular coagulation (DIC).

Tertiary protein structure refers to the three-dimensional arrangement of all the elements (polypeptide chains) of a single protein molecule. It is the highest level of structural organization and results from interactions between various side chains (R groups) of the amino acids that make up the protein. These interactions, which include hydrogen bonds, ionic bonds, van der Waals forces, and disulfide bridges, give the protein its unique shape and stability, which in turn determines its function. The tertiary structure of a protein can be stabilized by various factors such as temperature, pH, and the presence of certain ions. Any changes in these factors can lead to denaturation, where the protein loses its tertiary structure and thus its function.

Guanosine monophosphate (GMP) is a nucleotide that is a fundamental unit of genetic material in DNA and RNA. It consists of a guanine base, a pentose sugar (ribose in the case of RNA, deoxyribose in DNA), and one phosphate group. GMP plays crucial roles in various biochemical reactions within cells, including energy transfer and signal transduction pathways. Additionally, it is involved in the synthesis of important molecules like nucleic acids, neurotransmitters, and hormones.

Molecular probes, also known as bioprobes or molecular tracers, are molecules that are used to detect and visualize specific biological targets or processes within cells, tissues, or organisms. These probes can be labeled with a variety of detection methods such as fluorescence, radioactivity, or enzymatic activity. They can bind to specific biomolecules such as DNA, RNA, proteins, or lipids and are used in various fields including molecular biology, cell biology, diagnostic medicine, and medical research.

For example, a fluorescent molecular probe may be designed to bind specifically to a certain protein in a living cell. When the probe binds to its target, it emits a detectable signal that can be observed under a microscope, allowing researchers to track the location and behavior of the protein within the cell.

Molecular probes are valuable tools for understanding biological systems at the molecular level, enabling researchers to study complex processes such as gene expression, signal transduction, and metabolism in real-time. They can also be used in clinical settings for diagnostic purposes, such as detecting specific biomarkers of disease or monitoring the effectiveness of therapies.

Molecular evolution is the process of change in the DNA sequence or protein structure over time, driven by mechanisms such as mutation, genetic drift, gene flow, and natural selection. It refers to the evolutionary study of changes in DNA, RNA, and proteins, and how these changes accumulate and lead to new species and diversity of life. Molecular evolution can be used to understand the history and relationships among different organisms, as well as the functional consequences of genetic changes.

RNA folding, also known as RNA structure formation or RNA tertiary structure prediction, refers to the process by which an RNA molecule folds into a specific three-dimensional shape based on its primary sequence. This shape is determined by intramolecular interactions between nucleotides within the RNA chain, including base pairing (through hydrogen bonding) and stacking interactions. The folded structure of RNA plays a crucial role in its function, as it can create specific binding sites for proteins or other molecules, facilitate or inhibit enzymatic activity, or influence the stability and localization of the RNA within the cell.

RNA folding is a complex process that can be influenced by various factors such as temperature, ionic conditions, and molecular crowding. The folded structure of an RNA molecule can be predicted using computational methods, such as thermodynamic modeling and machine learning algorithms, which take into account the primary sequence and known patterns of base pairing and stacking interactions to generate a model of the three-dimensional structure. However, experimental techniques, such as chemical probing and crystallography, are often necessary to validate and refine these predictions.

Guanosine diphosphate (GDP) is a nucleotide that consists of a guanine base, a sugar molecule called ribose, and two phosphate groups. It is an ester of pyrophosphoric acid with the hydroxy group of the ribose sugar at the 5' position. GDP plays a crucial role as a secondary messenger in intracellular signaling pathways and also serves as an important intermediate in the synthesis of various biomolecules, such as proteins and polysaccharides.

In cells, GDP is formed from the hydrolysis of guanosine triphosphate (GTP) by enzymes called GTPases, which convert GTP to GDP and release energy that can be used to power various cellular processes. The conversion of GDP back to GTP can be facilitated by nucleotide diphosphate kinases, allowing for the recycling of these nucleotides within the cell.

It is important to note that while guanosine diphosphate has a significant role in biochemical processes, it is not typically associated with medical conditions or diseases directly. However, understanding its function and regulation can provide valuable insights into various physiological and pathophysiological mechanisms.

Adenosine monophosphate (AMP) is a nucleotide that is the monophosphate ester of adenosine, consisting of the nitrogenous base adenine attached to the 1' carbon atom of ribose via a β-N9-glycosidic bond, which in turn is esterified to a phosphate group. It is an important molecule in biological systems as it plays a key role in cellular energy transfer and storage, serving as a precursor to other nucleotides such as ADP and ATP. AMP is also involved in various signaling pathways and can act as a neurotransmitter in the central nervous system.

Thymine nucleotides are biochemical components that play a crucial role in the structure and function of DNA (deoxyribonucleic acid), which is the genetic material present in living organisms. A thymine nucleotide consists of three parts: a sugar molecule called deoxyribose, a phosphate group, and a nitrogenous base called thymine.

Thymine is one of the four nucleobases in DNA, along with adenine, guanine, and cytosine. It specifically pairs with adenine through hydrogen bonding, forming a base pair that is essential for maintaining the structure and stability of the double helix. Thymine nucleotides are linked together by phosphodiester bonds between the sugar molecules of adjacent nucleotides, creating a long, linear polymer known as a DNA strand.

In summary, thymine nucleotides are building blocks of DNA that consist of deoxyribose, a phosphate group, and the nitrogenous base thymine, which pairs with adenine in the double helix structure.

Cytosine nucleotides are the chemical units or building blocks that make up DNA and RNA, one of the four nitrogenous bases that form the rung of the DNA ladder. A cytosine nucleotide is composed of a cytosine base attached to a sugar molecule (deoxyribose in DNA and ribose in RNA) and at least one phosphate group. The sequence of these nucleotides determines the genetic information stored in an organism's genome. In particular, cytosine nucleotides pair with guanine nucleotides through hydrogen bonding to form base pairs that are held together by weak interactions. This pairing is specific and maintains the structure and integrity of the DNA molecule during replication and transcription.

Nucleic acid hybridization is a process in molecular biology where two single-stranded nucleic acids (DNA, RNA) with complementary sequences pair together to form a double-stranded molecule through hydrogen bonding. The strands can be from the same type of nucleic acid or different types (i.e., DNA-RNA or DNA-cDNA). This process is commonly used in various laboratory techniques, such as Southern blotting, Northern blotting, polymerase chain reaction (PCR), and microarray analysis, to detect, isolate, and analyze specific nucleic acid sequences. The hybridization temperature and conditions are critical to ensure the specificity of the interaction between the two strands.

I apologize for the confusion, but "Flexiviridae" is not a medical term or concept. It is actually a taxonomic family of viruses that includes several plant pathogens. The members of this family have single-stranded, positive-sense RNA genomes and flexuous filamentous virions. They are responsible for causing various diseases in plants, such as mosaics, rots, and necrosis.

Species specificity is a term used in the field of biology, including medicine, to refer to the characteristic of a biological entity (such as a virus, bacterium, or other microorganism) that allows it to interact exclusively or preferentially with a particular species. This means that the biological entity has a strong affinity for, or is only able to infect, a specific host species.

For example, HIV is specifically adapted to infect human cells and does not typically infect other animal species. Similarly, some bacterial toxins are species-specific and can only affect certain types of animals or humans. This concept is important in understanding the transmission dynamics and host range of various pathogens, as well as in developing targeted therapies and vaccines.

Bacterial RNA refers to the genetic material present in bacteria that is composed of ribonucleic acid (RNA). Unlike higher organisms, bacteria contain a single circular chromosome made up of DNA, along with smaller circular pieces of DNA called plasmids. These bacterial genetic materials contain the information necessary for the growth and reproduction of the organism.

Bacterial RNA can be divided into three main categories: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). mRNA carries genetic information copied from DNA, which is then translated into proteins by the rRNA and tRNA molecules. rRNA is a structural component of the ribosome, where protein synthesis occurs, while tRNA acts as an adapter that brings amino acids to the ribosome during protein synthesis.

Bacterial RNA plays a crucial role in various cellular processes, including gene expression, protein synthesis, and regulation of metabolic pathways. Understanding the structure and function of bacterial RNA is essential for developing new antibiotics and other therapeutic strategies to combat bacterial infections.

A consensus sequence in genetics refers to the most common nucleotide (DNA or RNA) or amino acid at each position in a multiple sequence alignment. It is derived by comparing and analyzing several sequences of the same gene or protein from different individuals or organisms. The consensus sequence provides a general pattern or motif that is shared among these sequences and can be useful in identifying functional regions, conserved domains, or evolutionary relationships. However, it's important to note that not every sequence will exactly match the consensus sequence, as variations can occur naturally due to mutations or genetic differences among individuals.

A viral genome is the genetic material (DNA or RNA) that is present in a virus. It contains all the genetic information that a virus needs to replicate itself and infect its host. The size and complexity of viral genomes can vary greatly, ranging from a few thousand bases to hundreds of thousands of bases. Some viruses have linear genomes, while others have circular genomes. The genome of a virus also contains the information necessary for the virus to hijack the host cell's machinery and use it to produce new copies of the virus. Understanding the genetic makeup of viruses is important for developing vaccines and antiviral treatments.

Viral genes refer to the genetic material present in viruses that contains the information necessary for their replication and the production of viral proteins. In DNA viruses, the genetic material is composed of double-stranded or single-stranded DNA, while in RNA viruses, it is composed of single-stranded or double-stranded RNA.

Viral genes can be classified into three categories: early, late, and structural. Early genes encode proteins involved in the replication of the viral genome, modulation of host cell processes, and regulation of viral gene expression. Late genes encode structural proteins that make up the viral capsid or envelope. Some viruses also have structural genes that are expressed throughout their replication cycle.

Understanding the genetic makeup of viruses is crucial for developing antiviral therapies and vaccines. By targeting specific viral genes, researchers can develop drugs that inhibit viral replication and reduce the severity of viral infections. Additionally, knowledge of viral gene sequences can inform the development of vaccines that stimulate an immune response to specific viral proteins.

High-throughput nucleotide sequencing, also known as next-generation sequencing (NGS), refers to a group of technologies that allow for the rapid and parallel determination of nucleotide sequences of DNA or RNA molecules. These techniques enable the sequencing of large numbers of DNA or RNA fragments simultaneously, resulting in the generation of vast amounts of sequence data in a single run.

High-throughput sequencing has revolutionized genomics research by allowing for the rapid and cost-effective sequencing of entire genomes, transcriptomes, and epigenomes. It has numerous applications in basic research, including genome assembly, gene expression analysis, variant detection, and methylation profiling, as well as in clinical settings, such as diagnosis of genetic diseases, identification of pathogens, and monitoring of cancer progression and treatment response.

Some common high-throughput sequencing platforms include Illumina (sequencing by synthesis), Ion Torrent (semiconductor sequencing), Pacific Biosciences (single molecule real-time sequencing), and Oxford Nanopore Technologies (nanopore sequencing). Each platform has its strengths and limitations, and the choice of technology depends on the specific research question and experimental design.

Promoter regions in genetics refer to specific DNA sequences located near the transcription start site of a gene. They serve as binding sites for RNA polymerase and various transcription factors that regulate the initiation of gene transcription. These regulatory elements help control the rate of transcription and, therefore, the level of gene expression. Promoter regions can be composed of different types of sequences, such as the TATA box and CAAT box, and their organization and composition can vary between different genes and species.

Nanotechnology is not a medical term per se, but it is a field of study with potential applications in medicine. According to the National Nanotechnology Initiative, nanotechnology is defined as "the understanding and control of matter at the nanoscale, at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications."

In the context of medicine, nanotechnology has the potential to revolutionize the way we diagnose, treat, and prevent diseases. Nanomedicine involves the use of nanoscale materials, devices, or systems for medical applications. These can include drug delivery systems that target specific cells or tissues, diagnostic tools that detect biomarkers at the molecular level, and tissue engineering strategies that promote regeneration and repair.

While nanotechnology holds great promise for medicine, it is still a relatively new field with many challenges to overcome, including issues related to safety, regulation, and scalability.

Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.

Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as α-helices and β-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.

Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

An allele is a variant form of a gene that is located at a specific position on a specific chromosome. Alleles are alternative forms of the same gene that arise by mutation and are found at the same locus or position on homologous chromosomes.

Each person typically inherits two copies of each gene, one from each parent. If the two alleles are identical, a person is said to be homozygous for that trait. If the alleles are different, the person is heterozygous.

For example, the ABO blood group system has three alleles, A, B, and O, which determine a person's blood type. If a person inherits two A alleles, they will have type A blood; if they inherit one A and one B allele, they will have type AB blood; if they inherit two B alleles, they will have type B blood; and if they inherit two O alleles, they will have type O blood.

Alleles can also influence traits such as eye color, hair color, height, and other physical characteristics. Some alleles are dominant, meaning that only one copy of the allele is needed to express the trait, while others are recessive, meaning that two copies of the allele are needed to express the trait.

Microfluidics is a multidisciplinary field that involves the study, manipulation, and control of fluids that are geometrically constrained to a small, typically sub-millimeter scale. It combines elements from physics, chemistry, biology, materials science, and engineering to design and fabricate microscale devices that can handle and analyze small volumes of fluids, often in the range of picoliters to microliters.

In medical contexts, microfluidics has numerous applications, including diagnostic testing, drug discovery, and personalized medicine. For example, microfluidic devices can be used to perform rapid and sensitive molecular assays for detecting pathogens or biomarkers in patient samples, as well as to screen drugs and evaluate their efficacy and toxicity in vitro.

Microfluidics also enables the development of organ-on-a-chip platforms that mimic the structure and function of human tissues and organs, allowing researchers to study disease mechanisms and test new therapies in a more physiologically relevant context than traditional cell culture models. Overall, microfluidics offers significant potential for improving healthcare outcomes by enabling faster, more accurate, and more cost-effective diagnostic and therapeutic strategies.

A conserved sequence in the context of molecular biology refers to a pattern of nucleotides (in DNA or RNA) or amino acids (in proteins) that has remained relatively unchanged over evolutionary time. These sequences are often functionally important and are highly conserved across different species, indicating strong selection pressure against changes in these regions.

In the case of protein-coding genes, the corresponding amino acid sequence is deduced from the DNA sequence through the genetic code. Conserved sequences in proteins may indicate structurally or functionally important regions, such as active sites or binding sites, that are critical for the protein's activity. Similarly, conserved non-coding sequences in DNA may represent regulatory elements that control gene expression.

Identifying conserved sequences can be useful for inferring evolutionary relationships between species and for predicting the function of unknown genes or proteins.

Proteins are complex, large molecules that play critical roles in the body's functions. They are made up of amino acids, which are organic compounds that are the building blocks of proteins. Proteins are required for the structure, function, and regulation of the body's tissues and organs. They are essential for the growth, repair, and maintenance of body tissues, and they play a crucial role in many biological processes, including metabolism, immune response, and cellular signaling. Proteins can be classified into different types based on their structure and function, such as enzymes, hormones, antibodies, and structural proteins. They are found in various foods, especially animal-derived products like meat, dairy, and eggs, as well as plant-based sources like beans, nuts, and grains.

"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.

Genetic models are theoretical frameworks used in genetics to describe and explain the inheritance patterns and genetic architecture of traits, diseases, or phenomena. These models are based on mathematical equations and statistical methods that incorporate information about gene frequencies, modes of inheritance, and the effects of environmental factors. They can be used to predict the probability of certain genetic outcomes, to understand the genetic basis of complex traits, and to inform medical management and treatment decisions.

There are several types of genetic models, including:

1. Mendelian models: These models describe the inheritance patterns of simple genetic traits that follow Mendel's laws of segregation and independent assortment. Examples include autosomal dominant, autosomal recessive, and X-linked inheritance.
2. Complex trait models: These models describe the inheritance patterns of complex traits that are influenced by multiple genes and environmental factors. Examples include heart disease, diabetes, and cancer.
3. Population genetics models: These models describe the distribution and frequency of genetic variants within populations over time. They can be used to study evolutionary processes, such as natural selection and genetic drift.
4. Quantitative genetics models: These models describe the relationship between genetic variation and phenotypic variation in continuous traits, such as height or IQ. They can be used to estimate heritability and to identify quantitative trait loci (QTLs) that contribute to trait variation.
5. Statistical genetics models: These models use statistical methods to analyze genetic data and infer the presence of genetic associations or linkage. They can be used to identify genetic risk factors for diseases or traits.

Overall, genetic models are essential tools in genetics research and medical genetics, as they allow researchers to make predictions about genetic outcomes, test hypotheses about the genetic basis of traits and diseases, and develop strategies for prevention, diagnosis, and treatment.

Drug delivery systems (DDS) refer to techniques or technologies that are designed to improve the administration of a pharmaceutical compound in terms of its efficiency, safety, and efficacy. A DDS can modify the drug release profile, target the drug to specific cells or tissues, protect the drug from degradation, and reduce side effects.

The goal of a DDS is to optimize the bioavailability of a drug, which is the amount of the drug that reaches the systemic circulation and is available at the site of action. This can be achieved through various approaches, such as encapsulating the drug in a nanoparticle or attaching it to a biomolecule that targets specific cells or tissues.

Some examples of DDS include:

1. Controlled release systems: These systems are designed to release the drug at a controlled rate over an extended period, reducing the frequency of dosing and improving patient compliance.
2. Targeted delivery systems: These systems use biomolecules such as antibodies or ligands to target the drug to specific cells or tissues, increasing its efficacy and reducing side effects.
3. Nanoparticle-based delivery systems: These systems use nanoparticles made of polymers, lipids, or inorganic materials to encapsulate the drug and protect it from degradation, improve its solubility, and target it to specific cells or tissues.
4. Biodegradable implants: These are small devices that can be implanted under the skin or into body cavities to deliver drugs over an extended period. They can be made of biodegradable materials that gradually break down and release the drug.
5. Inhalation delivery systems: These systems use inhalers or nebulizers to deliver drugs directly to the lungs, bypassing the digestive system and improving bioavailability.

Overall, DDS play a critical role in modern pharmaceutical research and development, enabling the creation of new drugs with improved efficacy, safety, and patient compliance.

Capillary electrophoresis (CE) is a laboratory technique used to separate and analyze charged particles such as proteins, nucleic acids, and other molecules based on their size and charge. In CE, the sample is introduced into a narrow capillary tube filled with a buffer solution, and an electric field is applied. The charged particles in the sample migrate through the capillary towards the electrode with the opposite charge, and the different particles become separated as they migrate based on their size and charge.

The separation process in CE is monitored by detecting the changes in the optical properties of the particles as they pass through a detector, typically located at the end of the capillary. The resulting data can be used to identify and quantify the individual components in the sample. Capillary electrophoresis has many applications in research and clinical settings, including the analysis of DNA fragments, protein identification and characterization, and the detection of genetic variations.

Viral proteins are the proteins that are encoded by the viral genome and are essential for the viral life cycle. These proteins can be structural or non-structural and play various roles in the virus's replication, infection, and assembly process. Structural proteins make up the physical structure of the virus, including the capsid (the protein shell that surrounds the viral genome) and any envelope proteins (that may be present on enveloped viruses). Non-structural proteins are involved in the replication of the viral genome and modulation of the host cell environment to favor viral replication. Overall, a thorough understanding of viral proteins is crucial for developing antiviral therapies and vaccines.

A haplotype is a group of genes or DNA sequences that are inherited together from a single parent. It refers to a combination of alleles (variant forms of a gene) that are located on the same chromosome and are usually transmitted as a unit. Haplotypes can be useful in tracing genetic ancestry, understanding the genetic basis of diseases, and developing personalized medical treatments.

In population genetics, haplotypes are often used to study patterns of genetic variation within and between populations. By comparing haplotype frequencies across populations, researchers can infer historical events such as migrations, population expansions, and bottlenecks. Additionally, haplotypes can provide information about the evolutionary history of genes and genomic regions.

In clinical genetics, haplotypes can be used to identify genetic risk factors for diseases or to predict an individual's response to certain medications. For example, specific haplotypes in the HLA gene region have been associated with increased susceptibility to certain autoimmune diseases, while other haplotypes in the CYP450 gene family can affect how individuals metabolize drugs.

Overall, haplotypes provide a powerful tool for understanding the genetic basis of complex traits and diseases, as well as for developing personalized medical treatments based on an individual's genetic makeup.

Deoxyadenine nucleotides are the chemical components that make up DNA, one of the building blocks of life. Specifically, deoxyadenine nucleotides contain a sugar molecule called deoxyribose, a phosphate group, and the nitrogenous base adenine. Adenine always pairs with thymine in DNA through hydrogen bonding. Together, these components form the building blocks of the genetic code that determines many of an organism's traits and characteristics.

Uridine Triphosphate (UTP) is a nucleotide that plays a crucial role in the synthesis and repair of DNA and RNA. It consists of a nitrogenous base called uracil, a pentose sugar (ribose), and three phosphate groups. UTP is one of the four triphosphates used in the biosynthesis of RNA during transcription, where it donates its uracil base to the growing RNA chain. Additionally, UTP serves as an energy source and a substrate in various biochemical reactions within the cell, including phosphorylation processes and the synthesis of glycogen and other molecules.

Chromosome mapping, also known as physical mapping, is the process of determining the location and order of specific genes or genetic markers on a chromosome. This is typically done by using various laboratory techniques to identify landmarks along the chromosome, such as restriction enzyme cutting sites or patterns of DNA sequence repeats. The resulting map provides important information about the organization and structure of the genome, and can be used for a variety of purposes, including identifying the location of genes associated with genetic diseases, studying evolutionary relationships between organisms, and developing genetic markers for use in breeding or forensic applications.

DNA-binding proteins are a type of protein that have the ability to bind to DNA (deoxyribonucleic acid), the genetic material of organisms. These proteins play crucial roles in various biological processes, such as regulation of gene expression, DNA replication, repair and recombination.

The binding of DNA-binding proteins to specific DNA sequences is mediated by non-covalent interactions, including electrostatic, hydrogen bonding, and van der Waals forces. The specificity of binding is determined by the recognition of particular nucleotide sequences or structural features of the DNA molecule.

DNA-binding proteins can be classified into several categories based on their structure and function, such as transcription factors, histones, and restriction enzymes. Transcription factors are a major class of DNA-binding proteins that regulate gene expression by binding to specific DNA sequences in the promoter region of genes and recruiting other proteins to modulate transcription. Histones are DNA-binding proteins that package DNA into nucleosomes, the basic unit of chromatin structure. Restriction enzymes are DNA-binding proteins that recognize and cleave specific DNA sequences, and are widely used in molecular biology research and biotechnology applications.

DNA repair is the process by which cells identify and correct damage to the DNA molecules that encode their genome. DNA can be damaged by a variety of internal and external factors, such as radiation, chemicals, and metabolic byproducts. If left unrepaired, this damage can lead to mutations, which may in turn lead to cancer and other diseases.

There are several different mechanisms for repairing DNA damage, including:

1. Base excision repair (BER): This process repairs damage to a single base in the DNA molecule. An enzyme called a glycosylase removes the damaged base, leaving a gap that is then filled in by other enzymes.
2. Nucleotide excision repair (NER): This process repairs more severe damage, such as bulky adducts or crosslinks between the two strands of the DNA molecule. An enzyme cuts out a section of the damaged DNA, and the gap is then filled in by other enzymes.
3. Mismatch repair (MMR): This process repairs errors that occur during DNA replication, such as mismatched bases or small insertions or deletions. Specialized enzymes recognize the error and remove a section of the newly synthesized strand, which is then replaced by new nucleotides.
4. Double-strand break repair (DSBR): This process repairs breaks in both strands of the DNA molecule. There are two main pathways for DSBR: non-homologous end joining (NHEJ) and homologous recombination (HR). NHEJ directly rejoins the broken ends, while HR uses a template from a sister chromatid to repair the break.

Overall, DNA repair is a crucial process that helps maintain genome stability and prevent the development of diseases caused by genetic mutations.

"Saccharomyces cerevisiae" is not typically considered a medical term, but it is a scientific name used in the field of microbiology. It refers to a species of yeast that is commonly used in various industrial processes, such as baking and brewing. It's also widely used in scientific research due to its genetic tractability and eukaryotic cellular organization.

However, it does have some relevance to medical fields like medicine and nutrition. For example, certain strains of S. cerevisiae are used as probiotics, which can provide health benefits when consumed. They may help support gut health, enhance the immune system, and even assist in the digestion of certain nutrients.

In summary, "Saccharomyces cerevisiae" is a species of yeast with various industrial and potential medical applications.

Microfluidic analytical techniques refer to the use of microfluidics, which is the manipulation of fluids in channels with dimensions of tens to hundreds of micrometers, for analytical measurements and applications. These techniques involve the integration of various functional components such as pumps, valves, mixers, and detectors onto a single chip or platform to perform chemical, biochemical, or biological analyses.

Microfluidic analytical techniques offer several advantages over traditional analytical methods, including reduced sample and reagent consumption, faster analysis times, increased sensitivity and throughput, and improved automation and portability. Examples of microfluidic analytical techniques include lab-on-a-chip devices, digital microfluidics, bead-based assays, and micro total analysis systems (μTAS). These techniques have found applications in various fields such as diagnostics, drug discovery, environmental monitoring, and food safety.

Base composition in genetics refers to the relative proportion of the four nucleotide bases (adenine, thymine, guanine, and cytosine) in a DNA or RNA molecule. In DNA, adenine pairs with thymine, and guanine pairs with cytosine, so the base composition is often expressed in terms of the ratio of adenine + thymine (A-T) to guanine + cytosine (G-C). This ratio can vary between species and even between different regions of the same genome. The base composition can provide important clues about the function, evolution, and structure of genetic material.

A genetic template refers to the sequence of DNA or RNA that contains the instructions for the development and function of an organism or any of its components. These templates provide the code for the synthesis of proteins and other functional molecules, and determine many of the inherited traits and characteristics of an individual. In this sense, genetic templates serve as the blueprint for life and are passed down from one generation to the next through the process of reproduction.

In molecular biology, the term "template" is used to describe the strand of DNA or RNA that serves as a guide or pattern for the synthesis of a complementary strand during processes such as transcription and replication. During transcription, the template strand of DNA is transcribed into a complementary RNA molecule, while during replication, each parental DNA strand serves as a template for the synthesis of a new complementary strand.

In genetic engineering and synthetic biology, genetic templates can be manipulated and modified to introduce new functions or alter existing ones in organisms. This is achieved through techniques such as gene editing, where specific sequences in the genetic template are targeted and altered using tools like CRISPR-Cas9. Overall, genetic templates play a crucial role in shaping the structure, function, and evolution of all living organisms.

Introns are non-coding sequences of DNA that are present within the genes of eukaryotic organisms, including plants, animals, and humans. Introns are removed during the process of RNA splicing, in which the initial RNA transcript is cut and reconnected to form a mature, functional RNA molecule.

After the intron sequences are removed, the remaining coding sequences, known as exons, are joined together to create a continuous stretch of genetic information that can be translated into a protein or used to produce non-coding RNAs with specific functions. The removal of introns allows for greater flexibility in gene expression and regulation, enabling the generation of multiple proteins from a single gene through alternative splicing.

In summary, introns are non-coding DNA sequences within genes that are removed during RNA processing to create functional RNA molecules or proteins.

Fluorescent dyes are substances that emit light upon excitation by absorbing light of a shorter wavelength. In a medical context, these dyes are often used in various diagnostic tests and procedures to highlight or mark certain structures or substances within the body. For example, fluorescent dyes may be used in imaging techniques such as fluorescence microscopy or fluorescence angiography to help visualize cells, tissues, or blood vessels. These dyes can also be used in flow cytometry to identify and sort specific types of cells. The choice of fluorescent dye depends on the specific application and the desired properties, such as excitation and emission spectra, quantum yield, and photostability.

Deoxyguanine nucleotides are chemical compounds that are the building blocks of DNA, one of the fundamental molecules of life. Specifically, deoxyguanine nucleotides contain a sugar molecule called deoxyribose, a phosphate group, and the nitrogenous base guanine.

Guanine is one of the four nitrogenous bases found in DNA, along with adenine, thymine, and cytosine. In DNA, guanine always pairs with cytosine through hydrogen bonding, forming a stable base pair that is crucial for maintaining the structure and integrity of the genetic code.

Deoxyguanine nucleotides are synthesized in cells during the process of DNA replication, which occurs prior to cell division. During replication, the double helix structure of DNA is unwound, and each strand serves as a template for the synthesis of a new complementary strand. Deoxyguanine nucleotides are added to the growing chain of nucleotides by an enzyme called DNA polymerase, which catalyzes the formation of a phosphodiester bond between the deoxyribose sugar of one nucleotide and the phosphate group of the next.

Abnormalities in the synthesis or metabolism of deoxyguanine nucleotides can lead to genetic disorders and cancer. For example, mutations in genes that encode enzymes involved in the synthesis of deoxyguanine nucleotides have been linked to inherited diseases such as xeroderma pigmentosum and Bloom syndrome, which are characterized by increased sensitivity to sunlight and a predisposition to cancer. Additionally, defects in the repair of damaged deoxyguanine nucleotides can lead to the accumulation of mutations and contribute to the development of cancer.

Untranslated regions (UTRs) are sections of an mRNA molecule that do not contain information for protein synthesis. There are two types of UTRs: 5' UTR, which is located at the 5' end of the mRNA molecule, and 3' UTR, which is located at the 3' end.

The 5' UTR typically contains regulatory elements that control the translation of the mRNA into protein. These elements can affect the efficiency and timing of translation, as well as the stability of the mRNA molecule. The 5' UTR may also contain upstream open reading frames (uORFs), which are short sequences that can be translated into small peptides and potentially regulate the translation of the main coding sequence.

The length and sequence composition of the 5' UTR can have significant impacts on gene expression, and variations in these regions have been associated with various diseases, including cancer and neurological disorders. Therefore, understanding the structure and function of 5' UTRs is an important area of research in molecular biology and genetics.

Exons are the coding regions of DNA that remain in the mature, processed mRNA after the removal of non-coding intronic sequences during RNA splicing. These exons contain the information necessary to encode proteins, as they specify the sequence of amino acids within a polypeptide chain. The arrangement and order of exons can vary between different genes and even between different versions of the same gene (alternative splicing), allowing for the generation of multiple protein isoforms from a single gene. This complexity in exon structure and usage significantly contributes to the diversity and functionality of the proteome.

SELEX is a well known selection method for fabrication and selection of nucleotide aptamers. SELEX is relatively limited by the ... When the probe surface neighboring an aptamer is blocked by an adjacent aptamer, the redox tag on the target-bound aptamer will ... The concentration of aptamer in solution that incubates a clean probe is found to be proportional to the density of aptamers ... In this method, libraries of aptamers are separated into aptamer particles and separated by FACS based on affinity. Only the ...
SPR imaging platform would be a good choice to characterize aptamer -protein interactions. To study the aptamer-protein ... Thiol groups are introduced on DNA nucleotides by N-hydroxysuccinimide (NHS). Target oligonucleotides having a primary amine ... The interaction of thrombin and the aptamer can be monitored on microarray in real-time during injections of thrombin at ... Daniel, C; Roupioz, Y; Gasparutti, D; Livache, T; Buhot, A (2013). "Solution-Phase vs Surface-Phase Aptamer-Protein Affinity ...
L-RNA aptamers are a form of aptamers. Due to their L-nucleotides, they are highly resistant to degradation by nucleases. L-RNA ... L-RNA aptamers themselves have low antigenicity. In contrast to other aptamers, L-RNA aptamers have high stability in blood ... such as PEGylated L-RNA aptamers, show a prolonged plasma half-life. Unlike other aptamers, L-RNA aptamers are not directly ... This information is used for the synthesis of the oligonucleotide's enantiomer, the L-RNA aptamer, using L-nucleotides. L-RNA ...
Spinach is an 84-nucleotide-long structure with two helical strands and an internal bulge with a G-quadruplex motif. It is at ... The aptamer was designed to be an RNA mimic of green fluorescent protein (GFP); similar to GFP for proteins, Spinach can be ... This aptamer was created using Systematic Evolution for Ligands by EXponential enrichment, or SELEX, which is also known as in ... Spinach is a synthetically derived RNA aptamer born out of the need for a way of studying the role of RNAs at the cellular ...
These nucleotide regions in the crcB RNA motif play important roles in the aptamer binding region for fluoride. Upon binding ...
... is a single-stranded DNA oligonucleotide aptamer with the nucleotide sequence 5'-GGT TGG TGT GGT TGG-3'. The proposed ... In 2014, the biotechnology company Berlin Cures GmbH was founded to investigate the aptamer with the nucleotide sequence GGT ... As of 2020, aptamers like BC-007 were being evaluated in several early-stage clinical trials for their potential safety and ... June 2020). "The aptamer BC 007 for treatment of dilated cardiomyopathy: evaluation in Doberman Pinschers of efficacy and ...
Aptamers have emerged as a novel category in the field of bioreceptors due to their wide applications ranging from biosensing ... Nucleotides with chemically modified sugars and bases have been incorporated into SELEX reactions to increase the chemical ... If a good binding affinity for the selected aptamer is not a concern, then an excess of target can be used to increase the ... There are aptamer applications for which a short sequence, and thus primer truncation, is desirable. An advancement on the ...
BNA nucleotides can be incorporated into DNA or RNA oligonucleotides at any desired position. Such oligomers are synthesized ... design and synthesis of RNA aptamers; siRNA; antisense probes; diagnostics; isolation; microarray analysis; Northern blotting; ... A bridged nucleic acid (BNA) is a modified RNA nucleotide. They are sometimes also referred to as constrained or inaccessible ... BNAs are structurally rigid oligo-nucleotides with increased binding affinities and stability. Chemical structures of BNA ...
Another example of an RNA aptamer therapeutic is NOX-A12, a 45 nucleotide RNA aptamer that is in clinical trials for chronic ... Broadly, aptamers are small molecules composed of either single-stranded DNA or RNA and are typically 20-100 nucleotides in ... In order to combat some of the in vivo limitations of RNA aptamers, various modifications can be added to the nucleotides to ... Originally approved in 2004 to treat age-related macular degeneration, Pegaptanib is a 28 nucleotide RNA aptamer that acts as a ...
PreQ1-I has a distinctly small aptamer, ranging from 25 to 45 nucleotides long, compared to the structures of PreQ1-II ... with an average of 58 nucleotides composing its aptamer, which forms as many as five base-paired substructures. PreQ1-III ... Binding of preQ1 to the aptamer domain promotes the sequestration of a part of SD sequence at the 5' end to the P2 stem of the ... In the native mRNA structure, binding of preQ1 to the aptamer region in the riboswitch leads to the formation of a terminator ...
Moreover, Chemically modified nucleotides in siRNA therapeutics improve chemical stability and efficacy, assist in targeting ... aptamers, peptides and antibodies have been covalently linked to siRNA in order to improve cellular uptake and target specific ... Oligonucleotides are single or double-stranded sequences of DNA or RNA of less than 30 nucleotides in length. Small interfering ... Elbashir, S M (2011). "Duplexes of 21-nucleotide RNAs mediate RNA interference in cultured mammalian cells". Nature. 411 (6836 ...
incorporated modified nucleotides in aptamers to introduce new confrontational features and high affinity interactions from the ... uses ACE to investigate protein-protein interactions using aptamers. A α-thrombin binding aptamer was labeled with 6- ... Aptamer-based affinity capillary electrophoresis is utilized for the analysis and modifications of specific affinity reagents. ... Modified aptamers ideally exhibit and high binding affinity, specificity, and nuclease resistance. Ren et al. ...
This would include the evolution of TNA aptamers that can bind to specific small molecule and protein targets, as well as the ... These structures demonstrate imperfect recognition of the incoming TNA nucleotide triphosphate and support the need for further ... 140, 5706-5713, (2018). Rangel, A. E., Chen, Z., Ayele, T. M. & Heemstra, J. M. In vitro selection of an XNA aptamer capable of ... The availability of TNA polymerases have enabled the in vitro selection of biologically stable TNA aptamers to both small ...
... aptamers, nucleotide MeSH D13.695.578.424.450 - oligodeoxyribonucleotides MeSH D13.695.578.424.450.275 - DNA primers MeSH ... thymine nucleotides MeSH D13.695.740.706.788 - thymidine monophosphate MeSH D13.695.740.850 - uracil nucleotides MeSH D13.695. ... deoxyguanine nucleotides MeSH D13.695.201.200 - deoxyuracil nucleotides MeSH D13.695.201.200.270 - fluorodeoxyuridylate MeSH ... deoxyadenine nucleotides MeSH D13.695.201.150 - deoxycytosine nucleotides MeSH D13.695.201.150.200 - deoxycytidine ...
... lacking the first and the last nucleotides of 29-mer form) nucleotides. This aptamer recognizes the exosite II of thrombin, ... Despite that this aptamer only shows moderate effect on fibrinogen regulation, the affinity of this aptamer is slightly higher ... The aptamer HD22 (also known as HTDQ) is an optimized aptamer with 29 (5'-AGTCCGTGGTAGGGCAGGTTGGGGTGACT-3') or 27 ( ... These two aptamers have high affinity and good specificity and have been widely studied and used for the development of aptamer ...
... but lacks most of the highly conserved nucleotides of SAM-III class. SAM-VI aptamers bind the cofactor S-adenosylmethinine SAM ...
... is an anticoagulation system cosisting of two drugs: pegnivacogin, a single-stranded 31-nucleotide aptamer that binds and ... Sinha, Gunjan (2013-12-01). "Regado's aptamer lines up against anticoagulants". Nature Biotechnology. 31 (12): 1060. doi: ... a novel actively controlled factor IX inhibitor using RNA aptamer technology for treatment of acute coronary syndrome". Future ... inhibits Factor IXa, and anivamersen, a complementary sequence reversal 15-nucleotide control agent. REG1 mechanism of action ...
... in position 74 of the aptamer domain, it has been found that conversion of a cytosine to a uracil changes an aptamer from being ... Such a conversion is owed to the ability of a nucleotide in position 74 to Watson-Crick base pair with the ligand in the ... The xpt guanine riboswitch aptamer is stabilized by guanine in a way that allows the riboswitch to more easily bind magnesium, ... In the absence of adenine, the aptamer domain of the riboswitch instead associates with the riboswitch expression platform, ...
Mutagenesis confirmed that changing nucleotides within the loop regions of this riboswitch altered the specificity for ligand ... classed as novel riboswitches as they deviate in sequence and structure within the loops regions that are required in aptamer ...
... and aptamer (nucleotide) complex among many other interesting studies. Molecular dynamics is used in many fields of science. ... and a 1063 nucleotide single stranded RNA genome. One key finding is that the capsid is very unstable when there is no RNA ... RNA structure in the ribosome and other large systems has been modeled with one pseudo-atom per nucleotide. Virtual cell ... "Electrical Stimulus Controlled Binding/Unbinding of Human Thrombin-Aptamer Complex". Scientific Reports. 6 (1): 37449. Bibcode: ...
CpG site A sequence of DNA in which a cytosine nucleotide is immediately followed by a guanine nucleotide on the same strand in ... aptamer artificial gene synthesis A set of laboratory methods used in the de novo synthesis of a gene (or any other nucleic ... anticodon A series of three consecutive nucleotides within a transfer RNA which complement the three nucleotides of a codon ... carbon is not connected to another nucleotide, and proceeding to the other terminal nucleotide, in which the 3' carbon is not ...
... alongside the four naturally occurring nucleotides, and by including individual artificial nucleotides in the culture media, ... In 2013, they applied the Ds-Px pair to DNA aptamer generation by in vitro selection (SELEX) and demonstrated the genetic ... 2006). "An unnatural hydrophobic base pair system: site-specific incorporation of nucleotide analogs into DNA and RNA". Nat. ... In May 2014, researchers announced that they had successfully introduced two new artificial nucleotides into bacterial DNA, ...
Several nucleotide positions are highly conserved, with many around the terminal loops involved in the pseudoknot interaction. ... a mechanism commonly used in engineered aptamers but not previously observed in nature. Cyclic di-GMP-II riboswitches are a ...
The function of the FMN riboswitch is twofold; first, riboswitches contain an aptamer component, which allows this RNA molecule ... FMN riboswitches also have various magnesium and potassium ions dispersed throughout the nucleotide structure, some of which ... and forms several water-mediated contacts with neighboring nucleotides. ... also suggest that these conformational changes in the structure of the FMN riboswitch are localized to specific nucleotide ...
Strands of DNA and RNA are formed by stringing together long chains of molecules called nucleotides. A nucleotide is made up of ... One experiment conducted at the University of Florida led to the production of an XNA aptamer by the AEGIS-SELEX (artificially ... Using a genetic code of six XNAs rather than the four naturally occurring DNA nucleotide bases yields endless opportunities for ... in XNA nucleotides, the deoxyribose and ribose sugar groups of DNA and RNA have been replaced with other chemical structures. ...
Allows construction of Cas9 complexes with protein binding cassettes, artificial aptamers, pools of random sequences as well as ... 80-250 nucleotides) to overcome this limitation. CRISPR-Display can therefore add larger RNA domains, like natural and lncRNA ... artificial aptamers and small molecules with varying size. While all the complexes were functional and viable, and successfully ... insert sequence was also determined through a set of unique sgRNA variants displaying cassettes of 25 random nucleotides. ...
Each three-nucleotide codon is translated into one of twenty naturally occurring amino acids. There is at least one tRNA for ... In 2013, they applied the Ds-Px pair to DNA aptamer generation by in vitro selection (SELEX) and demonstrated the genetic ... The 3'-end of the tRNA is mutated from CCA to CGA, while two cytidine nucleotides in the ribosomes A- and P-sites are mutated ... However, by co-mutating the binding nucleotides in such a way, that they can still base pair, the translational fidelity can be ...
AUCGAUUGAGCUCUAGCG UAGCUAACUCGAGAUCGC Chemical analogs of nucleotides can take the place of proper nucleotides and establish ... In 2013, they applied the Ds-Px pair to DNA aptamer generation by in vitro selection (SELEX) and demonstrated the genetic ... Hence, the number of total base pairs is equal to the number of nucleotides in one of the strands (with the exception of non- ... The nucleotides, which encoded RNA and proteins, were successfully replicated in vitro. Since then, Benner's team has been ...
The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of ... The hachimoji DNA system produced one type of catalytic RNA (ribozyme or aptamer) in vitro. Natural DNA is a molecule carrying ... DNA and RNA are naturally composed of four nucleotide bases that form hydrogen bonds in order to pair. Hachimoji DNA uses an ... In natural DNA, each nucleotide is composed of one of four nucleobases (cytosine [C], guanine [G], adenine [A] or thymine [T ...
He isolated the first aptamer (term he used for the first time). He isolated RNA enzymes with RNA ligase activity directly from ... Phosphorimidazolides were first proposed to be critical for early-earth nucleotide polymerization by Leslie E. Orgel and ... "The Mechanism of Nonenzymatic Template Copying with Imidazole-Activated Nucleotides". Angewandte Chemie International Edition. ...
... which is a light-up aptamer. Here, we propose to organize this aptamer into a split-aptamer system and determine the limit of ... Previous work by our group has been done to optimize the signal of the dapoxyl-binding aptamer (DAP), ... Aptamers have shown promising ability for detection in the subnanomolar range of nucleic acid targets with specificity down to ... and cost-effectiveness make these nucleic acid aptamers optimal bio-sensors. ...
1DB6: SOLUTION STRUCTURE OF THE DNA APTAMER 5-CGACCAACGTGTCGCCTGGTCG-3 COMPLEXED WITH ARGININAMIDE. ...
Interests: RNA; ncRNA; mirna; phage display; selex; small molecule screen; tissue culture; cancer; biophysics; aptamer; ... riboswitch; cyclic di nucleotide; Immunity; biosensor; aminoglycosides; in vitro screening. Dr. Sasa Bubanj ...
SELEX is a well known selection method for fabrication and selection of nucleotide aptamers. SELEX is relatively limited by the ... When the probe surface neighboring an aptamer is blocked by an adjacent aptamer, the redox tag on the target-bound aptamer will ... The concentration of aptamer in solution that incubates a clean probe is found to be proportional to the density of aptamers ... In this method, libraries of aptamers are separated into aptamer particles and separated by FACS based on affinity. Only the ...
Animals; Aptamers, Nucleotide; Cell Line; Cricetinae; Foot-and-Mouth Disease Virus; Gene Expression Regulation, Viral; Genetic ... The 3D(pol) aptamers appeared to be more effective than 2-C-methylcytidine (2CMC). Aptamers to components of the replication ... 3 more authors) (2014) Inhibition of the foot-and-mouth disease virus subgenomic replicon by RNA aptamers. Journal of General ... We have previously documented the inhibitory activity of RNA aptamers to the RNA-dependent RNA polymerase of foot-and-mouth ...
Aptamer library SELEX performance analysis algorithm based on percent GC nucleotide families ... Once an aptamer has been developed we also offer a service to optimise the performance of the aptamer on a range of assay ... Session 3: Aptamers as diagnostic tools. Chair Professor Said Ismail. 16.00: Dr David Bunka, The Aptamer Group, United Kingdom ... 2 Aptamer Group Limited, Bio Centre, Innovation Way, Heslington, York, UK. Abstract: Cell-based aptamer selection is an ...
Among the list of the artificial nucleotides, bridged nucleic acids (BNAs) appear to be the most promising ... Among the list of the artificial nucleotides, bridged nucleic acids (BNAs) appear to be the most promising new generation BNAs ... For the possible applications, BNAs can be used for antisense, antigene, aptamer development, and real-time clamp technology. ... There has been a growing interest in developing chemically modified nucleotides for diagnostics or therapeutics. ...
Keywords: Odds Ratio, Aptamers, Nucleotide, Acute Coronary Syndrome, Myocardial Infarction, Factor IXa, Cardiac Catheterization ...
Specific topics to be covered include aptamers, protein and RNA-based switches and sensors, unnatural amino acids and ... nucleotides, enzyme engineering, and the integration of these parts via synthetic biology efforts. Two lectures. ...
Aptamers, Nucleotide (MeSH) * Base Sequence (MeSH) * Biosensing Techniques (MeSH) * Fluorescence (MeSH) * Fluorescent Dyes ( ... A General Approach to the Construction of Structure-Switching Reporters from RNA Aptamers Academic Article ...
... and Nucleotide-binding oligomerization domain, Leucine rich Repeat and Pyrin domain containing proteins 1 and 3 (NALP1 and ... Oligonucleotide aptamers are well known for their stability and flexibility in conjugating various inflammatory molecules. In ... Beneficial Effects of Inflammatory Cytokine-Targeting Aptamers in an Animal Model of Chronic Prostatitis.. ... Beneficial Effects of Inflammatory Cytokine-Targeting Aptamers in an Animal Model of Chronic Prostatitis. ...
Typical length of ribonucleic acid aptamer Unspecified. 30-70. nucleotides. 105440. Rimmele M. Nucleic acid.... ... Number of different aptamer oligonucleotide sequences in first round of SELEX Unspecified. 10^15. Unitless. 105439. Rimmele M. ... Relevant examples of aptamer molecular beacons application targets, signal recorded and concentration range Unspecified. Table ...
Binding of the each modeled aptamer to the RBD was studied in terms of interactions between residues in protein and nucleotides ... Thus, a new aptamer Apt25 was designed. The procedure of 1) aptamer structure modeling/modification, 2) molecular docking, 3) ... Based on molecular docking results, the only one aptamer (Apt16) was selected from the library as a starting aptamer to the RBD ... aptamer receptor-binding domain SARS-CoV-2 selection oligonukleotidit kvanttikemia laskennallinen kemia koronavirukset ...
O-methylation for all C and U nucleotides). The PSMA aptamer served as a nonspecific control for the OPN aptamer when ... The OPN aptamer, 4-1BB aptamer, and 4-1BB-OPN bispecific aptamers for in vivo study have been previously described (43). ... 4-1BB aptamer (27 days), OPN aptamer (26 days), or a mixture of the 4-1BB and OPN aptamers (23 days) (n = 5 mice/group) (P , ... 4-1BB aptamer and OPN mRNA probe preparation for ISH. In order to make a DNA template for the 4-1BB aptamer, a T7 RNA ...
Here, a new type of stochastic sensor based on an αHL pore modified with an aptamer is described. The aptamer is bound to the ... Here, a new type of stochastic sensor based on an αHL pore modified with an aptamer is described. The aptamer is bound to the ... Here, a new type of stochastic sensor based on an αHL pore modified with an aptamer is described. The aptamer is bound to the ... Here, a new type of stochastic sensor based on an αHL pore modified with an aptamer is described. The aptamer is bound to the ...
Nucleotide Aptamers Medicine & Life Sciences 100% * RNA Probes Medicine & Life Sciences 96% ... Validation of RNA Aptamer Probes to Image Candida albicans in Paraffin-Embedded Sections of Wistar Rat Tongue. In: European ... Validation of RNA Aptamer Probes to Image Candida albicans in Paraffin-Embedded Sections of Wistar Rat Tongue. / Bachtiar, Boy ... Validation of RNA Aptamer Probes to Image Candida albicans in Paraffin-Embedded Sections of Wistar Rat Tongue. European Journal ...
The assay is many times more sensitive than conventional UV absorbance, and free nucleotides or short oligonucleotides of up to ... OliGreen reagent assays are routinely used for antisense oligonucleotides, aptamers, genomic DNA isolated under denaturing ... RiboGreen reagent does not detect significant sample contamination by free nucleotides and thus more accurately measures the ...
Here we used an aptamer displacement screen to identify SecinH3, a small molecule antagonist of cytohesins. The cytohesins are ... They are activated by guanine nucleotide exchange factors (GEFs), which facilitate the exchange of GDP for GTP1,2. This ... Controlling small guanine-nucleotide-exchange factor function through cytoplasmic RNA intramers. Proc. Natl Acad. Sci. USA 98, ... Jackson, C. L. & Casanova, J. E. Turning on ARF: the Sec7 family of guanine-nucleotide-exchange factors. Trends Cell Biol. 10, ...
Keywords: Alzheimers disease, biomarkers, blood, magnetic resonance imaging, nucleotide aptamers, proteome DOI: 10.3233/JAD- ...
Thrombotic disorders and their common clinical phenotypes of acute myocardial infarction, ischemic stroke, and venous thromboembolism are the proximate cause of substantial morbidity, mortality, and health care expenditures worldwide. Accordingly, therapies designed to attenuate thrombus initiation and propagation, reflecting integrated platelet-mediated and coagulation protease-mediated events, respectively, represent a standard of care. Unfortunately, there are numerous inherent limitations of existing therapies that include target nonselectivity, variable onset and offset of pharmacodynamic effects, a narrow efficacy-safety profile, and the absence of a safe and reliable platform for either accurate titration, based on existing patient-specific, disease-specific, and clinical conditions, or active reversibility. Herein, we summarize our experience with oligonucleotide antithrombotic agents and their complementary antidotes, targeting the platelet adhesive protein von Willebrand factor and the ...
Aptamers, Nucleotide (MeSH) * Organic Chemistry (Science Metrix) published in * ChemBioChem Journal Research. keywords * ... and aptamers. Research within this space has not only revealed the hidden talents of FNAs but has also laid important ... including naturally occurring ribozymes and riboswitches as well as artificially created DNAzymes and aptamers, have been ...
93del is a 16-nucleotide G-quadruplex-forming aptamer which can inhibit the activity of the HIV-1 integrase enzyme at nanomolar ... Crystal structures of an HIV-1 integrase aptamer: formation of a water-mediated A•G•G•G•G pentad in an interlocked G-quadruplex ... Ngo, K. H., Liew, C. W., Lattmann, S., Winnerdy, F. R. & Phan, A. T. (2022). Crystal structures of an HIV-1 integrase aptamer: ... To gain further insights on the structure of this unique aptamer, we have determined several high-resolution crystal structures ...
The application of Aptamer in biomarker discovery. Yongshu Li*, Winnie Wailing Tam, Yuanyuan Yu, Zhenjian Zhuo, Zhichao Xue, ... Dive into the research topics of The application of Aptamer in biomarker discovery. Together they form a unique fingerprint. ...
Nucleotide Aptamers 17% * Virus Latency 16% * Messenger RNA 13% Agriculture & Biology. * nuclear antigens 91% ...
Generative aptamer discovery using RaptGen. Iwano, N., Adachi, T., Aoki, K., Nakamura, Y. & Hamada, M., 2022 6月, In: Nature ... Prediction of RNA-protein interactions using a nucleotide language model. Yamada, K. & Hamada, M., 2022, In: Bioinformatics ... RaptRanker: In silico RNA aptamer selection from HT-SELEX experiment based on local sequence and structure information. Ishida ...
In vivo SELEX strategies to identify potent aptamer-drug conjugates for glioblastoma. Sarkaria, J. N. & Maher, L. L. J. ... Nucleotide Aptamers 37% * Pharmaceutical Preparations 20% * Venous Thrombosis After Traumatic Injury. Park, M. S. & Auton, M. T ...
Modified aptamers may show improved chemical diversity relative to aptamers composed entirely of natural DNA or RNA nucleotides ... Latham, A.J.; Johnson, R.; Toole, J.J. The application of a modified nucleotide in aptamer selection: Novel thrombin aptamers ... Circular bivalent aptamers (cb aptamers) were constructed from aptamers selected against live cancer cells, and were tested for ... Ligand-guided selection (LIGS) of aptamers is known to give aptamers with high specificity; however, these aptamers suffer from ...
... PubMed, SCI, Scopus, ESCI, PMC indexed ... 3.2 DNA Aptamers using UBPs. DNA Aptamers are in-vitro generated via an evolutional engineering method known as SELEX, ( ... Percze K, Mészáros T. Analysis of Modified Nucleotide Aptamer Library Generated by Thermophilic DNA Polymerases, ChemBioChem 21 ... Ligand-Guided Selection of Target-Specific Aptamers: A Screening Technology for Identifying Specific Aptamers Against Cell- ...
... an aptamer, an antibody, a antisense nucleotide, a siRNA, a shRNA, and a miRNA that specifically bind to TINAGL1 protein or a ... The agent may be selected from the group consisting of a primer, a probe, an antibody, a peptide, and an aptamer. ... The TINAGL1 inhibitor may be any one selected from the group consisting of a peptide, an aptamer, an antibody, a antisense ... nucleotide, a siRNA, a shRNA, and a miRNA that specifically bind to the TINAGL1 protein or a gene encoding the protein. ...
  • Nucleic acid aptamers are "short single-stranded DNA- or RNA-based oligonucleotides that can selectively bind to small molecular ligands or protein targets with high affinity and specificity, when folded into their unique three-dimensional structure" (1). (ucf.edu)
  • Aptamers 2016 will be co-hosted with our 2nd symposium on antisense and therapeutic oligonucleotides, Oligo 2016 , on 6th April 2016. (libpubmedia.co.uk)
  • The assay is many times more sensitive than conventional UV absorbance, and free nucleotides or short oligonucleotides of up to 6 bases do not interfere with the OliGreen ssDNA quantitation assay. (thermofisher.com)
  • OliGreen reagent assays are routinely used for antisense oligonucleotides, aptamers, genomic DNA isolated under denaturing conditions, PCR primers, sequencing primers, and single-stranded phage DNA. (thermofisher.com)
  • Aptamers are short single-stranded RNA or DNA oligonucleotides capable of folding into complex 3D structures, enabling them to bind to a large variety of targets ranging from small ions to an entire organism. (encyclopedia.pub)
  • Aptamers are single-stranded RNA or DNA oligonucleotides that fold up into a distinctive 3D structure capable of binding with high affinity and specificity to small molecules up to entire organisms, with nanomolar range dissociation constants. (encyclopedia.pub)
  • Nucleic acid-based aptamers were first described in 1990, where the first aptamers were in vitro selected using a random library of single-stranded oligonucleotides sequences [ 1 ] by a selection procedure known as systematic evolution of ligands by exponential enrichment (SELEX). (encyclopedia.pub)
  • Chemical modifications of aptamer oligonucleotides are needed mainly to enhance their resistance to nuclease degradation and lowering their renal filtration. (encyclopedia.pub)
  • Although monoclonal antibody therapeutics remain the mainstream in clinical practice, aptamers are synthetic oligonucleotides that encompass antibody-mimicking functions. (tmu.edu.tw)
  • Oligonucleotide aptamers are well known for their stability and flexibility in conjugating various inflammatory molecules. (iasp-pain.org)
  • The aptamer is bound to the pore by hybridization to an oligonucleotide that is attached covalently through a disulfide bond to a single cysteine residue near a mouth of the pore. (huji.ac.il)
  • The first oligonucleotide aptamer was isolated to bind with small molecules [ 2 ] . (encyclopedia.pub)
  • Studies have shown that small target molecules enable a greater signal gain for low density aptamer packing, while larger proteins as a target generate the greatest signal at intermediate probe packing densities. (wikipedia.org)
  • The levels of mononuclear cell infiltration, pro-inflammatory cytokine interleukin-1 beta (b), caspase-1 (casp-1), and Nucleotide-binding oligomerization domain, Leucine rich Repeat and Pyrin domain containing proteins 1 and 3 (NALP1 and NALP3) in the prostate of rats were increased seven days after carrageenan injection. (iasp-pain.org)
  • The genetic information of life on Earth have been conserved in natural nucleotides-A, G, C, T(U) forming two exclusive sets of base pairs A-T(U) & G-C, that complementing to the fundamental processes of DNA replication & RNA transcription by several polymerases and translation to functional proteins via ribosomal reactions. (fortuneonline.org)
  • The review also outlines the vast applications of UBPs as novel information storage components as well as in creation of semi-synthetic organisms expressing non canonical amino acids, high affinity aptamer generation, PCR based diagnostics and sitespecific labelling of RNAs. (fortuneonline.org)
  • Here, we report a novel high-affinity CTLA-4-antagonizing DNA aptamer (dissociation constant, 11.84 nM), aptCTLA-4, which was identified by cell-based SELEX and high-throughput sequencing. (tmu.edu.tw)
  • E-AB sensors are advantageous over previously reported aptamer-based sensors, such as fluorescence generating aptamers, due to their ability to detect target binding in vivo with real-time measurements. (wikipedia.org)
  • Due to its exceptional stability and unique topology, 93del has been used in many different studies involving DNA G-quadruplexes, such as DNA aptamer and multimer design, as well as DNA fluorescence research. (ntu.edu.sg)
  • ECHO probes have a fluorescence-labeled nucleotide in which two molecules of thiazole orange or its derivatives are linked covalently. (ne.jp)
  • The selectivity, low limit of detection, and cost-effectiveness make these nucleic acid aptamers optimal bio-sensors. (ucf.edu)
  • 2014), nucleic acid aptamers (Woo et al. (datexis.com)
  • Because nucleic acid aptamers have comparable binding affinities with corresponding antibodies, they are regarded as potential candidates for the development of therapeutic agents or diagnostic probes (Brody and Gold, 2000). (datexis.com)
  • The binding of the aptamer with the target protein produces a change in impedance of the membrane which is picked up by the electrochemical sensor using an impedance spectroscopy analyzer. (wikipedia.org)
  • In this work, in silico selection of DNA-aptamers to the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein was performed using molecular modeling methods. (jyu.fi)
  • Based on molecular docking results, the only one aptamer (Apt16) was selected from the library as a starting aptamer to the RBD protein. (jyu.fi)
  • Binding of the each modeled aptamer to the RBD was studied in terms of interactions between residues in protein and nucleotides in the aptamers. (jyu.fi)
  • Donaldson, J. G., Finazzi, D. & Klausner, R. D. Brefeldin A inhibits Golgi membrane-catalysed exchange of guanine nucleotide onto ARF protein. (nature.com)
  • Morinaga, N., Tsai, S.-C., Moss, J. & Vaughan, M. Isolation of a brefeldin A-inhibited guanine nucleotide-exchange protein for ADP ribosylation factor (ARF) 1 and ARF3 that contains a Sec7-like domain. (nature.com)
  • Based on cascade catalysis amplification driven by glucose oxidase (GOx), a sensitive electrochemical impedimetric aptasensor for protein (carcinoembryonic antigen, CEA as tested model) was proposed by using Cu-based metal-organic frameworks functionalized with Pt nanoparticles, aptamer, hemin and GOx (Pt@CuMOFs-hGq-GOx). (unboundmedicine.com)
  • In the present study, we isolated RNA aptamers specific to influenza NS1 protein. (datexis.com)
  • Unlike the wild-type 10-mer sequences, which bind 1 protein dimer/duplex, these 22-mer thiophosphate aptamers bind with a stoichiometry of 2 dimers/duplex. (utmb.edu)
  • Depending on the size and nature of target molecule, different aptamer packing densities favor signal gain. (wikipedia.org)
  • Aptamers have shown promising ability for detection in the subnanomolar range of nucleic acid targets with specificity down to single nucleotide variations (2). (ucf.edu)
  • SNP analysis: You can detect difference of a single nucleotide. (ne.jp)
  • Among the list of the artificial nucleotides, bridged nucleic acids (BNAs) appear to be the most promising new generation BNAs to date in view of the usage for applications. (biosyn.com)
  • Thus, while inculcating the UBPs in a DNA structure, their aromatic scaffolds must exhibit hydrophobic packing and must have hydrogen bond donor groups for the artificial nucleotides to interact with polymerases for their efficient incorporation in the non-template strand to bind with their UB partner in template strand [1-3]. (fortuneonline.org)
  • Aptamer target-binding specificity and affinity are obtained using a Darwinian evolution screening technology called systematic evolution of ligands by exponential enrichment (SELEX). (encyclopedia.pub)
  • The SELEX methodology is quite similar for both DNA and RNA aptamers. (encyclopedia.pub)
  • The standard SELEX procedure allows the identification of specific RNA binders (aptamers) for the target of interest. (elsevierpure.com)
  • Herein, we described a strategy integrating high-throughput (HT) sequencing with conventional SELEX followed by bioinformatic analysis to identify aptamers with high binding affinity and target specificity to unravel the sequence-structure motifs of pre-miRNA, which is essential for binding to the recently developed new water-soluble small-molecule CMBL3aL. (elsevierpure.com)
  • We use 80 nucleotide sequences in our aptamer selection process, with a random region of 40 nucleotides. (neoaptamers.com)
  • Using DNA and RNA aptamers sequences, targeting ability can be bestowed to the polymerized nucleotides. (duke.edu)
  • Using a 22-nucleotide-long duplex random library, nanomolar binding, specific 22-mer thiophosphate backbone substitution sequences (at dA positions only) were selected. (utmb.edu)
  • Objective This study aimed to validate the use of Ca-apt-1, an RNA aptamer, that we generated previously as a probe for immunostaining of Candida albicans in rat tongue paraffin-fixed tissue sections Material and Methods The performance of Ca-apt-1 as a detector molecule was compared with that of anti- C. albicans polyclonal antibody (PcAb), which was used as a positive control. (unair.ac.id)
  • Here we used an aptamer displacement screen to identify SecinH3, a small molecule antagonist of cytohesins. (nature.com)
  • The length of an aptamer is not a function of its size but it's ability to bind to a target molecule. (neoaptamers.com)
  • Many approaches have been introduced to promote the stability of aptamers without altering their binding affinity and specificity against their targets. (encyclopedia.pub)
  • 93del is a 16-nucleotide G-quadruplex-forming aptamer which can inhibit the activity of the HIV-1 integrase enzyme at nanomolar concentration. (ntu.edu.sg)
  • The selected RNA aptamers bind to NS1 specifically and inhibit the interaction between NS1 and TRIM25. (datexis.com)
  • These unnatural nucleotides are chemically synthesized to bind each other via non-standard hydrogen bonding, hydrophobic interactions and other shape complementing patterns [2,5]. (fortuneonline.org)
  • Aptamers have been selected that bind tightly to the nuclear factor for human IL6 (NF-IL6), a basic leucine zipper transcription factor involved in the induction of acute-phase responsive and cytokine gene promotors in response to inflammation. (utmb.edu)
  • We are developing a platform for targeted and sustained delivery of anti-metabolic nucleotide analogs for chemotherapy. (duke.edu)
  • In addition to the well-known method of conjugating chemotherapeutic drugs to biopolymers and synthetic polymers, our lab also works on polymerization of nucleotide analogs using enzymatic routes. (duke.edu)
  • There has been a growing interest in developing chemically modified nucleotides for diagnostics or therapeutics. (biosyn.com)
  • Modified aptamers may show improved chemical diversity relative to aptamers composed entirely of natural DNA or RNA nucleotides and expand their applications in diagnostics, therapeutics, and nanotechnology [ 1 ] . (encyclopedia.pub)
  • The use of aptamers in large arrays for molecular diagnostics. (colorado.edu)
  • For Apt16/RBD complex, molecular dynamic and quantum chemical calculations revealed the pairs of nucleotides and amino acids whose contribution to the binding between aptamer and RBD is the lar gest. (jyu.fi)
  • In the synthesis process for an aptamer there is failure to appropriate add the next nucleotide approximately 0.8% of the time. (neoaptamers.com)
  • The cost of aptamer synthesis is based on the cost of the components used to create it. (neoaptamers.com)
  • Additionally, chemical modifications, in some cases, may increase the aptamer-binding affinity [ 13 ] . (encyclopedia.pub)
  • Aptamers to components of the replication complex are therefore useful molecular tools for studying viral replication and also have potential as diagnostic molecules in the future. (whiterose.ac.uk)
  • A new computational approach to aptamer in silico selection is based on a cycle of simulations, including the stages of molecular modeling, molecular docking, molecular dynamic simulations, and quantum chemical calculations. (jyu.fi)
  • The procedure of 1) aptamer structure modeling/modification, 2) molecular docking, 3) molecular dynamic simulations, 4) quantum chemical calculations was performed sev-eral times. (jyu.fi)
  • The proposed computational approach to selection and refinement of aptamers is universal and can be used for wide range of molecular ligands and targets. (jyu.fi)
  • Functional nucleic acids (FNAs), including naturally occurring ribozymes and riboswitches as well as artificially created DNAzymes and aptamers, have been popular molecular toolboxes for diverse applications. (mcmaster.ca)
  • We exploit different DNA polymerases and molecular biology tools to generate oligomers of nucleotide drugs. (duke.edu)
  • Previous structural analyses of 93del using NMR spectroscopy have shown that the aptamer forms an interlocked G-quadruplex structure in K+ solution. (ntu.edu.sg)
  • To confirm the fidelity of this approach, we investigated the binding of CMBL3aL to the identified motifs by surface plasmon resonance (SPR) spectroscopy and its potential regulatory activity on dicer-mediated cleavage of the obtained aptamers and endogenous pre-miRNAs comprising the identified motif in its hairpin loop. (elsevierpure.com)
  • Moreover, introducing chemical modifications into nucleic acid libraries increases the interaction capabilities of aptamers and thereby their target spectrum [ 12 ] . (encyclopedia.pub)
  • Focused aptamer libraries are constructed in accordance with a proteome (i.e., complex mixture of native biomolecules). (duke.edu)
  • Targets on which aptamer selection is conducted against are diverse, ranging from ions to whole living cells. (encyclopedia.pub)
  • An electrochemical aptamer-based (E-AB) biosensor has the ability to generate an electrochemical signal in response to specific target binding in vivo The signal is measured by a change in Faradaic current passed through an electrode. (wikipedia.org)
  • Aptamers need to be stabilized for in vivo use against nuclease degradation, and their small size makes them susceptible to renal filtration. (encyclopedia.pub)
  • Aptamer: You can detect the small molecules by ECHO-installed aptamer. (ne.jp)
  • Through sandwich-type reaction of target CEA and CEA aptamers (Apt1 and Apt2), the obtained Pt@CuMOFs-hGq-GOx as signal transduction probes (STPs) was captured to the modified electrode interface. (unboundmedicine.com)
  • In ECHO probes, a hybridization-dependent fluorescent nucleotide regulated by the H-aggregation of thiazole orange organic dyes (D 514 ) is incorporated into specific sequence contexts and serves as fluorescent detection readout for target nucleic acids. (ne.jp)
  • Our study demonstrates the developmental pipeline of a functional CTLA-4-targeting aptamer and suggests a translational potential for aptCTLA-4. (tmu.edu.tw)
  • The symposium will address therapeutic, diagnostic, analytical as well as basic research applications of aptamers and invites proposals for podium (now closed! (libpubmedia.co.uk)
  • We also found that viral replication was suppressed in the presence of aptamers, which suggests that the selected RNA aptamers can be developed as a useful therapeutic agent in future. (datexis.com)
  • Here, we propose to organize this aptamer into a split-aptamer system and determine the limit of detection and selectivity for a target gene in Mycobacterium tuberculosis . (ucf.edu)
  • Aptamer-based nanopores have the potential to be integrated into arrays for the parallel detection of multiple analytes. (huji.ac.il)
  • When the probe surface neighboring an aptamer is blocked by an adjacent aptamer, the redox tag on the target-bound aptamer will not have room to come into contact with the electrode, therefore failing to report target binding. (wikipedia.org)
  • Helms, J. B. & Rothman, J. E. Inhibition by brefeldin A of a Golgi membrane enzyme that catalyses exchange of guanine nucleotide bound to ARF. (nature.com)
  • CEA aptamer loaded onto Pt@CuMOFs was bound with hemin to form hemin@G-quadruplex (hGq) with mimicking peroxidase activity. (unboundmedicine.com)
  • Several groups have developed synthetic unnatural nucleotides that can form unnatural base pairs with their complementary synthetic bases. (fortuneonline.org)
  • The extra nucleotides on a longer aptamer are not involved in the binding event and can reduce both the rate of complex formation by getting in the way, and the rate of complexes coming apart by reducing the stability of the aptamer structure. (neoaptamers.com)
  • View a selection of Aptamers 2016 photos on the INSOAP website . (libpubmedia.co.uk)
  • Aptamer selection against novel infections is a complicated and time-consuming approach. (jyu.fi)
  • RiboGreen reagent does not detect significant sample contamination by free nucleotides and thus more accurately measures the amount of intact RNA in potentially degraded samples. (thermofisher.com)
  • Chemical Modifications of Aptamers" Encyclopedia , https://encyclopedia.pub/entry/16686 (accessed December 05, 2023). (encyclopedia.pub)
  • We show that the binding of thrombin to a 15-mer DNA aptamer, which forms a cation-stabilized quadruplex, alters the ionic current through the pore. (huji.ac.il)
  • The FNA species to be discussed include ribozymes, riboswitches, G‐quadruplex‐based peroxidase mimicking DNAzymes, RNA‐cleaving DNAzymes, and aptamers. (mcmaster.ca)
  • Four electrode method has also been demonstrated in an electrochemical nanoporous alumina membrane sensor, where the aptamer was grafted onto the membrane and not on the electrode. (wikipedia.org)
  • Upon target binding, the aptamer changes structure by folding, bringing the redox reporter closer to the gold electrode. (wikipedia.org)
  • This approach could be beneficial in cases where the electric field of the electrode can change the aptamer structure or the biointerface which may decrease the sensing ability. (wikipedia.org)
  • To gain further insights on the structure of this unique aptamer, we have determined several high-resolution crystal structures of 93del and its variants. (ntu.edu.sg)
  • However, more effort is needed to identify and characterize the sequence-structure motifs in the aptamers important for binding to the target. (elsevierpure.com)
  • The aptamer probe packing density, the nature of the self-assembling monolayer, and the ACV frequency are factors that affect detecting and measuring of signal. (wikipedia.org)
  • The concentration of aptamer and the surface chemistry of the self-assembling monolayer (SAM) enable variations of desired probe packing density. (wikipedia.org)
  • The concentration of aptamer in solution that incubates a clean probe is found to be proportional to the density of aptamers that are immobilized on the probe. (wikipedia.org)
  • It also explores aspects of biomolecular engineering and various bioconjugation methods to confer nuclease resistance to the nucleotide oligomers. (duke.edu)