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Heteroresistance
Heteroresistance is a phenotype in which a bacterial isolate contains sub-populations of cells with increased antibiotic resistance Antimicrobial resistance (AMR) occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials. All classes of microbes can evolve resistance. Fungi evolve antifungal resistance. Viruses evolve antiviral resistance. ... when compared with the susceptible main population. This phenomenon is known to be highly prevalent among several antibiotic classes and bacterial isolates and associated with treatment failure through the enrichment of low frequencies of resistant subpopulations in the presence of antibiotics. Heteroresistance is known to be highly unstable, meaning that the resistance sub-population can revert to susceptibility within a limited number of generations of growth in the absence of antibiotic. Regarding the instability and the transient characteristic of heteroresistance subpopulations, the detection of this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code, or its genotype, and the influence of environmental factors. Both factors may interact, further affecting phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and then again in his 1982 book ''The Extended Phenotype'' suggested that one can regard bird nests and other built structures such as cad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variant (biology)
In microbiology and virology, the term variant or genetic variant is used to describe a subtype of a microorganism that is genetically distinct from a main strain, but not sufficiently different to be termed a distinct strain. A similar distinction is made in botany between different cultivated varieties of a species of plant, termed cultivars. Viruses SARS-CoV-2 It was said in 2013 that "there is no universally accepted definition for the terms 'strain', 'variant', and 'isolate' in the virology community, and most virologists simply copy the usage of terms from others". The lack of precise definition continued in 2020; in the context of the Variant of Concern 202012/01 version of the SARS-CoV-2 virus, the website of the US Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibiotic Resistance
Antimicrobial resistance (AMR) occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials. All classes of microbes can evolve resistance. Fungi evolve antifungal resistance. Viruses evolve antiviral resistance. Protozoa evolve antiprotozoal resistance, and bacteria evolve antibiotic resistance. Those bacteria that are considered extensively drug resistant (XDR) or totally drug-resistant (TDR) are sometimes called "superbugs".A.-P. Magiorakos, A. Srinivasan, R. B. Carey, Y. Carmeli, M. E. Falagas, C. G. Giske, S. Harbarth, J. F. Hinndler ''et al''Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria... Clinical Microbiology and Infection, Vol 8, Iss. 3 first published 27 July 2011 ia Wiley Online Library Retrieved 28 August 2020 Although antimicrobial resistance is a naturally-occurring process, it is often the result of improper usage of the drugs and management of the infections. Antibiotic resistance is a major subset ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tandem Gene
Tandem, or in tandem, is an arrangement in which a team of machines, animals or people are lined up one behind another, all facing in the same direction. The original use of the term in English was in ''tandem harness'', which is used for two or more draft horses, or other draft animals, harnessed in a single line one behind another, as opposed to a pair, harnessed side by side, or a team of several pairs. The tandem harness allows additional animals to provide pulling power for a vehicle designed for a single animal. The English word ''tandem'' derives from the Latin adverb , meaning ''at length'' or ''finally''. It is a word play, using the Latin phrase (referring to time, not position) for English "at length, lengthwise". Tandem bicycles are named for their tandem seating, a more common arrangement than side-by-side "sociable" seating. ''Tandem'' can also be used more generally to refer to any group of persons or objects working together, not necessarily in line. Automob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplification (molecular Biology)
Gene duplication (or chromosomal duplication or gene amplification) is a major mechanism through which new genetic material is generated during molecular evolution. It can be defined as any duplication of a region of DNA that contains a gene. Gene duplications can arise as products of several types of errors in DNA replication and DNA repair, repair machinery as well as through fortuitous capture by selfish genetic elements. Common sources of gene duplications include ectopic recombination, retrotransposon, retrotransposition event, aneuploidy, polyploidy, and replication slippage. Mechanisms of duplication Ectopic recombination Duplications arise from an event termed unequal crossing-over that occurs during meiosis between misaligned homologous chromosomes. The chance of it happening is a function of the degree of sharing of repetitive elements between two chromosomes. The products of this recombination are a duplication at the site of the exchange and a reciprocal deletio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
