In biology, phase variation is a method for dealing with rapidly varying environments without requiring random mutation. It involves the variation of protein expression, frequently in an on-off fashion, within different parts of a bacterial population. As such the phenotype can switch at frequencies that are much higher (sometimes >1%) than classical mutation rates. Phase variation contributes to virulence by generating heterogeneity. Although it has been most commonly studied in the context of immune evasion, it is observed in many other areas as well and is employed by various types of bacteria, including Salmonella species.
Salmonella use this technique to switch between different types of the protein flagellin. As a result, flagella with different structures are assembled. Once an adaptive response has been mounted against one type of flagellin, or if a previous encounter has left the adaptive immune system ready to deal with one type of flagellin, switching types renders previously high affinity antibodies, TCRs, and BCRs ineffective against the flagella.
biology, phasevariation is a method for dealing with rapidly varying environments without requiring random mutation. It involves the variation of protein...
resistance and has also impeded vaccine development. Phasevariation is similar to antigenic variation, but instead of changes at the genetic level altering...
of the mechanisms of antigenic escape. It is related to phasevariation. Antigenic variation not only enables the pathogen to avoid the immune response...
especially important in uropathogenic Escherichia coli. The gene undergoes phasevariation mediated via two recombinases and is a model example of site specific...
Self-phase modulation (SPM), an effect due to the optical Kerr effect (and possibly higher-order nonlinearities) caused by the temporal variation in the...
on one side of the waist to the far field on the other side. This phasevariation is not observable in most experiments. It is, however, of theoretical...
proteins. They also found more genes that undergo phasevariation than any pathogen then known. Phasevariation is a mechanism that helps the pathogen to evade...
is called bacterial pneumonia. S. pneumoniae undergoes spontaneous phasevariation, changing between transparent and opaque colony phenotypes. The transparent...
Phase modulation (PM) is a modulation pattern for conditioning communication signals for transmission. It encodes a message signal as variations in the...
completed. Slipped strand mispairing has also been shown to function as a phasevariation mechanism in certain bacteria. Slippage occurs through five main stages:...
Zimmerman CU, Stiedl T, Rosengarten R, Spergser J (March 2009). "Alternate phasevariation in expression of two major surface membrane proteins (MBA and UU376)...
polysaccharides (an example of phasevariation), some of which the phage uses for host-recognition. With phasevariation, B. intestinalis can maintain...
to synthesize more than one type of LOS, a characteristic known as phasevariation. Additionally, Neisseria gonorrhoeae, as well as Neisseria meningitidis...
vary slightly due to dispersion, this is negligible compared to the variation in phase difference according to the wavelength of the light due to the fixed...
but for you are not. This variation is called Postal Rules in honor of the group of postal employees who have played Phase 10 everyday during lunch since...
interference, in frequency regions of rapid phasevariation. Only regions of slow phasevariation (stationary phase) will contribute significantly to the reconstruction...
particularly image processing, total variation denoising, also known as total variation regularization or total variation filtering, is a noise removal process...
experience unacceptable toxicity. Variations of this design exist, but most are similar. Multiple ascending dose (Phase Ib): Multiple ascending dose studies...
than in adults. With N-acetyltransferases (involved in Phase II reactions), individual variation creates a group of people who acetylate slowly (slow acetylators)...
radio frequency communications systems. All these frequencies and phasevariations must be estimated using the information in the received signal to reproduce...
thermodynamics, and other related fields like physics and biology, a phase transition (or phase change) is the physical process of transition between one state...
known as phase variable regulons) mediate a coordinated change in the expression of multiple genes or proteins. This occurs via phasevariation of a single...
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