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Prophage SVG
A prophage is a bacteriophage (often shortened to "phage") genome that is integrated into the circular bacterial chromosome or exists as an extrachromosomal plasmid within the bacterial cell. Integration of prophages into the bacterial host is the characteristic step of the lysogenic cycle of temperate phages. Prophages remain latent in the genome through multiple cell divisions until activation by an external factor, such as UV light, leading to production of new phage particles that will lyse the cell and spread. As ubiquitous mobile genetic elements, prophages play important roles in bacterial genetics and evolution, such as in the acquisition of virulence factors. Prophage induction Upon detection of host cell damage by UV light or certain chemicals, the prophage is excised from the bacterial chromosome in a process called prophage induction. After induction, viral replication begins via the lytic cycle. In the lytic cycle, the virus commandeers the cell's reproductive mach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prophage
A prophage is a bacteriophage (often shortened to "phage") genome that is integrated into the circular bacterial chromosome or exists as an extrachromosomal plasmid within the bacterial cell (biology), cell. Integration of prophages into the bacterial host is the characteristic step of the lysogenic cycle of Temperateness (virology), temperate phages. Prophages remain viral latency, latent in the genome through multiple cell divisions until activation by an external factor, such as UV light, leading to production of new phage particles that will Lysis, lyse the cell and spread. As ubiquitous mobile genetic elements, prophages play important roles in bacterial genetics and evolution, such as in the acquisition of virulence factors. Prophage induction Upon detection of host cell damage by UV light or certain chemicals, the prophage is excised from the bacterial chromosome in a process called prophage induction. After induction, viral replication begins via the lytic cycle. In the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolling Circle Replication
Rolling circle replication (RCR) is a process of unidirectional nucleic acid replication that can rapidly synthesize multiple copies of circular molecules of DNA or RNA, such as plasmids, the genomes of bacteriophages, and the circular RNA genome of viroids. Some eukaryotic viruses also replicate their DNA or RNA via the rolling circle mechanism. As a simplified version of natural rolling circle DNA replication, replication, an isothermal DNA amplification technique, rolling circle amplification was developed. The RCA mechanism is widely used in molecular biology and biomedical nanotechnology, especially in the field of Biosensor, biosensing (as a method of signal amplification). Circular DNA replication Rolling circle DNA replication is initiated by an initiator protein encoded by the plasmid or bacteriophage DNA, which nicks one strand of the double-stranded, circular DNA molecule at a site called the double-strand origin, or DSO. The initiator protein remains bound to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Staph Infections
A staphylococcal infection or staph infection is an infection caused by members of the ''Staphylococcus'' genus of bacteria. These bacteria commonly inhabit the skin and nose where they are innocuous, but may enter the body through cuts or abrasions which may be nearly invisible. Once inside the body, the bacteria may spread to a number of body systems and organs, including the heart, where the toxins produced by the bacteria may cause cardiac arrest. Once the bacterium has been identified as the cause of the illness, treatment is often in the form of antibiotics and, where possible, drainage of the infected area. However, many strains of this bacterium have become antibiotic resistant; for those with these kinds of infection, the body's own immune system is the only defense against the disease. If that system is weakened or compromised, the disease may progress rapidly. Anyone can contract staph, but pregnant women, children, and people with chronic diseases or who are immuno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Conversion
Gene conversion is the process by which one DNA sequence replaces a homologous sequence such that the sequences become identical after the conversion. Gene conversion can be either allelic, meaning that one allele of the same gene replaces another allele, or ectopic, meaning that one Sequence homology#Paralogy, paralogous DNA sequence converts another. Allelic gene conversion Allelic gene conversion occurs during meiosis when homologous recombination between heterozygotic sites results in a mismatch in base pairing. This mismatch is then recognized and corrected by the cellular machinery causing one of the alleles to be converted to the other. This can cause non-Mendelian segregation of alleles in germ cells. Nonallelic/ectopic gene conversion Recombination occurs not only during meiosis, but also as a mechanism for repair of double-strand breaks (DSBs) caused by DNA damage. These DSBs are usually repaired using the sister chromatid of the broken duplex and not the homologous chrom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RecA
RecA is a 38 kilodalton protein essential for the repair and maintenance of DNA in bacteria. Structural and functional homologs to RecA have been found in all kingdoms of life. RecA serves as an archetype for this class of homologous DNA repair proteins. The homologous protein is called RAD51 in eukaryotes and RadA in archaea. RecA has multiple activities, all related to DNA repair. In the bacterial SOS response, it functions as a co-protease in the autocatalytic cleavage of the LexA repressor and the λ repressor. Function Homologous recombination The RecA protein binds strongly and in long clusters to ssDNA to form a nucleoprotein filament. The protein has multiple DNA binding sites, and thus can hold a single strand and double strand together. This feature makes it possible to catalyze a DNA synapsis reaction between a DNA double helix and a complementary region of single-stranded DNA. The RecA-ssDNA filament searches for sequence similarity along the dsDNA. A disordere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homologous Recombination
Homologous recombination is a type of genetic recombination in which genetic information is exchanged between two similar or identical molecules of double-stranded or single-stranded nucleic acids (usually DNA as in Cell (biology), cellular organisms but may be also RNA in viruses). Homologous recombination is widely used by cells to accurately DNA repair, repair harmful DNA breaks that occur on both strands of DNA, known as double-strand breaks (DSB), in a process called homologous recombinational repair (HRR). Homologous recombination also produces new combinations of DNA sequences during meiosis, the process by which eukaryotes make gamete cells, like sperm and ovum, egg cells in animals. These new combinations of DNA represent genetic variation in offspring, which in turn enables populations to Adaptation, adapt during the course of evolution. Homologous recombination is also used in horizontal gene transfer to exchange genetic material between different strains and species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambda Phage
Lambda phage (coliphage λ, scientific name ''Lambdavirus lambda'') is a bacterial virus, or bacteriophage, that infects the bacterial species ''Escherichia coli'' (''E. coli''). It was discovered by Esther Lederberg in 1950. The wild type of this virus has a Temperate (virology), temperate life cycle that allows it to either reside within the genome of its host through lysogeny or enter into a lytic phase, during which it kills and lyses the cell to produce offspring. Lambda strains, mutated at specific sites, are unable to lysogenize cells; instead, they grow and enter the lytic cycle after superinfecting an already lysogenized cell. The phage particle consists of a head (also known as a capsid), a tail, and tail fibers (see image of virus below). The head contains the phage's double-strand linear DNA genome. During infections, the phage particle recognizes and binds to its host, ''E. coli'', causing DNA in the head of the phage to be ejected through the tail into the cytopla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Conjugation
Bacterial conjugation is the transfer of genetic material between Bacteria, 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 cycle, parasexual mode of reproduction in bacteria. It is a mechanism of horizontal gene transfer as are Transformation (genetics), transformation and Transduction (genetics), 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 biogenesis, 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 trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Repressor Protein
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 r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biofilm
A biofilm is a Syntrophy, syntrophic Microbial consortium, community of microorganisms in which cell (biology), cells cell adhesion, stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPSs). The cells within the biofilm produce the EPS components, which are typically a polymeric combination of extracellular polysaccharides, proteins, lipids and DNA. Because they have a three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as "cities for microbes". Biofilms may form on living (biotic) or non-living (abiotic) surfaces and can be common in natural, industrial, and hospital settings. They may constitute a microbiome or be a portion of it. The microbial cells growing in a biofilm are physiology, physiologically distinct from planktonic cells of the same organism, which, by contrast, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deoxycholic Acid
Deoxycholic acid is a bile acid. Deoxycholic acid is one of the secondary bile acids, which are metabolic byproducts of intestinal bacteria. The two primary bile acids secreted by the liver are cholic acid and chenodeoxycholic acid. Bacteria metabolize chenodeoxycholic acid into the secondary bile acid lithocholic acid, and they metabolize cholic acid into deoxycholic acid. There are additional secondary bile acids, such as ursodeoxycholic acid. Deoxycholic acid is soluble in alcohol and acetic acid. When pure, it exists in a white to off-white crystalline powder form. Deoxycholic acid is available as a generic medication in the United States as of April 2021, sold under the brand name Kybella among others. Applications Deoxycholic acid has been used since its discovery in various fields of human medicine. In the human body deoxycholic acid is used in the emulsification of fats for absorption in the intestine. It has, in some countries (including Switzerland) been licensed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
