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Tn5 Transposon
A transposase is any of a class of enzymes capable of binding to the end of a transposon and catalysing its movement to another part of a genome, typically by a cut-and-paste mechanism or a replicative mechanism, in a process known as transposition. The word "transposase" was first coined by the individuals who cloned the enzyme required for transposition of the Tn3 transposon. The existence of transposons was postulated in the late 1940s by Barbara McClintock, who was studying the inheritance of maize, but the actual molecular basis for transposition was described by later groups. McClintock discovered that some segments of chromosomes changed their position, jumping between different loci or from one chromosome to another. The repositioning of these transposons (which coded for color) allowed other genes for pigment to be expressed. Transposition in maize causes changes in color; however, in other organisms, such as bacteria, it can cause antibiotic resistance. Transposition is al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Next-generation Sequencing
Massive parallel sequencing or massively parallel sequencing is any of several high-throughput approaches to DNA sequencing using the concept of massively parallel processing; it is also called next-generation sequencing (NGS) or second-generation sequencing. Some of these technologies emerged between 1994 and 1998 and have been commercially available since 2005. These technologies use miniaturized and parallelized platforms for sequencing of 1 million to 43 billion short reads (50 to 400 bases each) per instrument run. Many NGS platforms differ in engineering configurations and sequencing chemistry. They share the technical paradigm of massive parallel sequencing via spatially separated, clonally amplified DNA templates or single DNA molecules in a flow cytometry, flow cell. This design is very different from that of Sanger sequencing—also known as capillary sequencing or first-generation sequencing—which is based on electrophoretic separation of chain-termination products produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regulator Gene
A regulator gene, regulator, or regulatory gene is a gene involved in controlling the expression of one or more other genes. Regulatory sequences, which encode regulatory genes, are often at the five prime end (5') to the start site of transcription of the gene they regulate. In addition, these sequences can also be found at the three prime end (3') to the transcription start site. In both cases, whether the regulatory sequence occurs before (5') or after (3') the gene it regulates, the sequence is often many kilobases away from the transcription start site. A regulator gene may encode a protein, or it may work at the level of RNA, as in the case of genes encoding microRNAs. An example of a regulator gene is a gene that codes for a repressor protein that inhibits the activity of an operator (a gene which binds repressor proteins thus inhibiting the translation of RNA to protein via RNA polymerase). In prokaryotes, regulator genes often code for repressor proteins. Repressor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activator (genetics)
A transcriptional activator is a protein (transcription factor) that increases transcription of a gene or set of genes. Activators are considered to have ''positive'' control over gene expression, as they function to promote gene transcription and, in some cases, are required for the transcription of genes to occur. Most activators are DNA-binding proteins that bind to enhancers or promoter-proximal elements. The DNA site bound by the activator is referred to as an "activator-binding site". The part of the activator that makes protein–protein interactions with the general transcription machinery is referred to as an "activating region" or "activation domain". Most activators function by binding sequence-specifically to a regulatory DNA site located near a promoter and making protein–protein interactions with the general transcription machinery (RNA polymerase and general transcription factors), thereby facilitating the binding of the general transcription machinery to the prom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Cassette
In biology, a gene cassette is a type of mobile genetic element that contains a gene and a recombination site. Each cassette usually contains a single gene and tends to be very small; on the order of 500–1000 base pairs. They may exist incorporated into an integron or freely as circular DNA. Gene cassettes can move around within an organism's genome or be transferred to another organism in the environment via horizontal gene transfer. These cassettes often carry antibiotic resistance genes. An example would be the '' kanMX'' cassette which confers kanamycin (an antibiotic) resistance upon bacteria. Integrons Integrons are genetic structures in bacteria which express and are capable of acquiring and exchanging gene cassettes. The integron consists of a promoter, an attachment site, and an integrase gene that encodes a site-specific recombinase There are three classes of integrons described. The mobile units that insert into integrons are gene cassettes. For cassettes that ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integron
Integrons are genetic mechanisms that allow bacteria to adapt and evolve rapidly through the stockpiling and expression of new genes. These genes are embedded in a specific genetic structure called gene cassette (a term that is lately changing to integron cassette) that generally carries one promoterless open reading frame (ORF) together with a recombination site (''attC''). Integron cassettes are incorporated to the ''attI'' site of the integron platform by site-specific recombination reactions mediated by the integrase. Discovery Integrons were initially discovered on conjugative plasmids through their role in antibiotic resistance. Indeed, these mobile integrons, as they are now known, can carry a variety of cassettes containing genes that are almost exclusively related to antibiotic resistance. Further studies have come to the conclusion that integrons are chromosomal elements, and that their mobilisation onto plasmids has been fostered by transposons and selected by the intens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptomycin
Streptomycin is an antibiotic medication used to treat a number of bacterial infections, including tuberculosis, ''Mycobacterium avium'' complex, endocarditis, brucellosis, ''Burkholderia'' infection, plague, tularemia, and rat bite fever. For active tuberculosis it is often given together with isoniazid, rifampicin, and pyrazinamide. It is administered by injection into a vein or muscle. Common side effects include vertigo, vomiting, numbness of the face, fever, and rash. Use during pregnancy may result in permanent deafness in the developing baby. Use appears to be safe while breastfeeding. It is not recommended in people with myasthenia gravis or other neuromuscular disorders. Streptomycin is an aminoglycoside. It works by blocking the ability of 30S ribosomal subunits to make proteins, which results in bacterial death. Albert Schatz first isolated streptomycin in 1943 from ''Streptomyces griseus''. It is on the World Health Organization's List of Essential Medicine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethoprim
Trimethoprim (TMP) is an antibiotic used mainly in the treatment of bladder infections. Other uses include for middle ear infections and travelers' diarrhea. With sulfamethoxazole or dapsone it may be used for ''Pneumocystis'' pneumonia in people with HIV/AIDS. It is taken by mouth. Common side effects include nausea, changes in taste, and rash. Rarely it may result in blood problems such as not enough platelets or white blood cells. Trimethoprim may cause sun sensitivity. There is evidence of potential harm during pregnancy in some animals but not humans. It works by blocking folate metabolism via dihydrofolate reductase in some bacteria which results in their death. Trimethoprim was first used in 1962. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. Medical uses It is primarily used in the treatment of urinary tract infections, although it may be used against any susceptible aerobic bacterial species. It may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmids
A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; however, plasmids are sometimes present in archaea and eukaryotic organisms. In nature, plasmids often carry genes that benefit the survival of the organism and confer selective advantage such as antibiotic resistance. While chromosomes are large and contain all the essential genetic information for living under normal conditions, plasmids are usually very small and contain only additional genes that may be useful in certain situations or conditions. Artificial plasmids are widely used as vectors in molecular cloning, serving to drive the replication of recombinant DNA sequences within host organisms. In the laboratory, plasmids may be introduced into a cell via transformation. Synthetic plasmids are available for procurement over the intern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escherichia Coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escherichia'' that is commonly found in the lower intestine of warm-blooded organisms. Most ''E. coli'' strains are harmless, but some serotypes ( EPEC, ETEC etc.) can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains do not cause disease in humans and are part of the normal microbiota of the gut; such strains are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of ''E. coli'' benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between ''E. col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mobile Genetic Element
Mobile genetic elements (MGEs) sometimes called selfish genetic elements are a type of genetic material that can move around within a genome, or that can be transferred from one species or replicon to another. MGEs are found in all organisms. In humans, approximately 50% of the genome is thought to be MGEs. MGEs play a distinct role in evolution. Gene duplication events can also happen through the mechanism of MGEs. MGEs can also cause mutations in protein coding regions, which alters the protein functions. These mechanisms can also rearrange genes in the host genome generating variation. These mechanism can increase fitness by gaining new or additional functions. An example of MGEs in evolutionary context are that virulence factors and antibiotic resistance genes of MGEs can be transported to share genetic code with neighboring bacteria. However, MGEs can also decrease fitness by introducing disease-causing alleles or mutations. The set of MGEs in an organism is called a mobilome, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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