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RK2 Plasmid
The RK2 Plasmid is a broad-host-range plasmid belonging to the incP incompatibility group It is notable for its ability to replicate in a wide variety of single-celled organisms, which makes it suitable as a genetic engineering tool. It is capable of transfer, replication, and maintenance in most genera of Gram-negative bacteria. RK2 may sometimes be referred to as pRK2, which is also the name of another, unrelated plasmid. The IncP-1 plasmid group (IncP plasmids in ''Escherichia coli'') of which RK2 is a part has been described as "highly potent, self-transmissible, selfish DNA molecules with a complicated regulatory circuit" Discovery RK2 was first isolated in connection with an outbreak of antibiotic-resistant ''Pseudomonas aeruginosa'' and ''Klebsiella aerogenes'' in Birmingham in 1969, as one of a family of plasmids implicated in transfer of Ampicillin resistance between bacterial strains.LEWIS C. INGRAM, M. H. RICHMOND, AND R. B. SYKES: "Molecular Characterization of the R Fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmid
A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; however, plasmids are sometimes present in archaea and eukaryotic organisms. In nature, plasmids often carry genes that benefit the survival of the organism and confer selective advantage such as antibiotic resistance. While chromosomes are large and contain all the essential genetic information for living under normal conditions, plasmids are usually very small and contain only additional genes that may be useful in certain situations or conditions. Artificial plasmids are widely used as vectors in molecular cloning, serving to drive the replication of recombinant DNA sequences within host organisms. In the laboratory, plasmids may be introduced into a cell via transformation. Synthetic plasmids are available for procurement over the int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Cycle
The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and subsequently the partitioning of its cytoplasm, chromosomes and other components into two daughter cells in a process called cell division. In cells with nuclei ( eukaryotes, i.e., animal, plant, fungal, and protist cells), the cell cycle is divided into two main stages: interphase and the mitotic (M) phase (including mitosis and cytokinesis). During interphase, the cell grows, accumulating nutrients needed for mitosis, and replicates its DNA and some of its organelles. During the mitotic phase, the replicated chromosomes, organelles, and cytoplasm separate into two new daughter cells. To ensure the proper replication of cellular components and division, there are control mechanisms known as cell cycle checkpoints after each of the key s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mobile Genetic Elements
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] |
National Center For Biotechnology Information
The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is located in Bethesda, Maryland, and was founded in 1988 through legislation sponsored by US Congressman Claude Pepper. The NCBI houses a series of databases relevant to biotechnology and biomedicine and is an important resource for bioinformatics tools and services. Major databases include GenBank for DNA sequences and PubMed, a bibliographic database for biomedical literature. Other databases include the NCBI Epigenomics database. All these databases are available online through the Entrez search engine. NCBI was directed by David Lipman, one of the original authors of the BLAST sequence alignment program and a widely respected figure in bioinformatics. GenBank NCBI had responsibility for making available the GenBank DNA seq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recombinant Protein
Recombinant DNA (rDNA) molecules are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) that bring together genetic material from multiple sources, creating DNA sequence, sequences that would not otherwise be found in the genome. Recombinant DNA is the general name for a piece of DNA that has been created by combining at least two fragments from two different sources. Recombinant DNA is possible because DNA molecules from all organisms share the same chemical structure, and differ only in the nucleotide sequence within that identical overall structure. Recombinant DNA molecules are sometimes called chimeric DNA, because they can be made of material from two different species, like the mythical Chimera (mythology), chimera. R-DNA technology uses palindromic sequences and leads to the production of sticky and blunt ends. The DNA sequences used in the construction of recombinant DNA molecules can originate from any species. For example, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloramphenicol
Chloramphenicol is an antibiotic useful for the treatment of a number of bacterial infections. This includes use as an eye ointment to treat conjunctivitis. By mouth or by injection into a vein, it is used to treat meningitis, plague, cholera, and typhoid fever. Its use by mouth or by injection is only recommended when safer antibiotics cannot be used. Monitoring both blood levels of the medication and blood cell levels every two days is recommended during treatment. Common side effects include bone marrow suppression, nausea, and diarrhea. The bone marrow suppression may result in death. To reduce the risk of side effects treatment duration should be as short as possible. People with liver or kidney problems may need lower doses. In young children a condition known as gray baby syndrome may occur which results in a swollen stomach and low blood pressure. Its use near the end of pregnancy and during breastfeeding is typically not recommended. Chloramphenicol is a broad- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Origin Of Transfer
An origin of transfer (''oriT'') is a short sequence ranging from 40-500 base pairs in length that is necessary for the transfer of DNA from a gram-negative bacterial donor to recipient during bacterial conjugation. The transfer of DNA is a critical component for antimicrobial resistance within bacterial cells and the ''oriT'' structure and mechanism within plasmid DNA is complimentary for its function in bacterial conjugation. The first ''oriT'' to be identified and cloned was on the RK2 (IncP) conjugative plasmid, which was done by Guiney and Helinski in 1979. Structure ''oriT'' regions are central to the process of transferring DNA from the donor to recipient and contain several important regions that facilitate this: # ''nic'' site: where the unwound plasmid DNA is cut; usually site-specific. # An inverted repeat sequence: signals the end of replication of donor DNA and is responsible for transfer frequency, plasmid mobilization, and secondary DNA structure formation. # AT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Origin Of Replication
The origin of replication (also called the replication origin) is a particular sequence in a genome at which replication is initiated. Propagation of the genetic material between generations requires timely and accurate duplication of DNA by semiconservative replication prior to cell division to ensure each daughter cell receives the full complement of chromosomes. Material was copied from this source, which is available under Creative Commons Attribution 4.0 International License This can either involve the replication of DNA in living organisms such as prokaryotes and eukaryotes, or that of DNA or RNA in viruses, such as double-stranded RNA viruses. Synthesis of daughter strands starts at discrete sites, termed replication origins, and proceeds in a bidirectional manner until all genomic DNA is replicated. Despite the fundamental nature of these events, organisms have evolved surprisingly divergent strategies that control replication onset. Although the specific replicatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selectable Marker
A selectable marker is a gene introduced into a cell, especially a bacterium or to cells in culture, that confers a trait suitable for artificial selection. They are a type of reporter gene used in laboratory microbiology, molecular biology, and genetic engineering to indicate the success of a transfection or other procedure meant to introduce foreign DNA into a cell. Selectable markers are often antibiotic resistance genes (''An antibiotic resistance marker is a gene that produces a protein that provides cells expressing this protein with resistance to an antibiotic.''). Bacteria that have been subjected to a procedure to introduce foreign DNA are grown on a medium containing an antibiotic, and those bacterial colonies that can grow have successfully taken up and expressed the introduced genetic material. Normally the genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline or kanamycin, etc., are considered useful selectable markers for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Repressor
In molecular genetics, a repressor is a DNA- or RNA-binding protein that inhibits the expression of one or more genes by binding to the operator or associated silencers. A DNA-binding repressor blocks the attachment of RNA polymerase to the promoter, thus preventing transcription of the genes into messenger RNA. An RNA-binding repressor binds to the mRNA and prevents translation of the mRNA into protein. This blocking or reducing of expression is called repression. Function If an inducer, a molecule that initiates the gene expression, is present, then it can interact with the repressor protein and detach it from the operator. RNA polymerase then can transcribe the message (expressing the gene). A co-repressor is a molecule that can bind to the repressor and make it bind to the operator tightly, which decreases transcription. A repressor that binds with a co-repressor is termed an ''aporepressor'' or ''inactive repressor''. One type of aporepressor is the trp re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Conjugation
Bacterial conjugation is the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells. This takes place through a pilus. It is a parasexual mode of reproduction in bacteria. It is a mechanism of horizontal gene transfer as are transformation and transduction although these two other mechanisms do not involve cell-to-cell contact. Classical ''E. coli'' bacterial conjugation is often regarded as the bacterial equivalent of sexual reproduction or mating since it involves the exchange of genetic material. However, it is not sexual reproduction, since no exchange of gamete occurs, and indeed no generation of a new organism: instead an existing organism is transformed. During classical ''E. coli'' conjugation the ''donor'' cell provides a conjugative or mobilizable genetic element that is most often a plasmid or transposon. Most conjugative plasmids have systems ensuring that the ''recipient'' cell does n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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