Lethal Fraction
Lethal Fraction - Related Videos
02:41
Lethal Alleles
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2021
Agouti: A Lethal Allele Lucien Cuénot discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is responsible for the color of the coat in mice. This gene codes for an agouti-signaling protein, which is responsible for melanin distribution in mammals. The wild-type allele gives rise to gray-brown coat color in mice, while the mutant allele gives rise to yellow coat color. In addition to coat color, the agouti gene is associated with the yellow...
09:09
Lethality Bioassay Using Artemia salina L.
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Cited by 20 •
2022
This work aims to evaluate and review the Artemia salina lethality bioassay procedure, also identified as brine shrimp lethality assay. This simple and cheap method gives information about the general toxicity (considered as a preliminary toxicity evaluation) of samples, namely, natural products.
08:39
Shifting Zebrafish Lethal Skeletal Mutant Penetrance by Progeny Testing
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Cited by 8 •
2017
The goal of this protocol is to alter the penetrance of lethal skeletal mutant phenotypes in zebrafish by selective breeding. Lethal mutants cannot be grown to adulthood and bred themselves, therefore this protocol describes a method for tracking and selecting penetrance through multiple generations by progeny testing.
10:09
Fractional Distillation
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2023
Source: Laboratory of Dr. Nicholas Leadbeater — University of Connecticut Distillation is perhaps the most common laboratory technique employed by chemists for the purification of organic liquids. Compounds in a mixture with different boiling points separate into individual components when the mixture is carefully distilled. The two main types of distillation are "simple distillation" and "fractional distillation", and both are widely used in organic chemistry laboratories. Simple distillation...
14:40
Long-term Lethal Toxicity Test with the Crustacean Artemia franciscana
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Cited by 34 •
2012
This study concerns the development and standardization of a valuable methodological protocol to determine long-term (14 days) lethal toxicity exerted by chemical substances, industrial wastewater or sewage and liquid environmental samples on the saltwater crustacean, Artemia franciscana.
FAQs
Increasing concentration, dose, intensity, or exposure duration commonly increases the lethal fraction, producing a dose-response pattern. This relationship indicates that mortality is associated with exposure conditions rather than being treated as a single fixed outcome. Examining the pattern helps researchers evaluate how strongly a harmful agent affects a population and identify exposure levels associated with greater susceptibility.
The relevant variables include the agent’s concentration or dose, its intensity, and the duration of exposure. Because lethal fraction is linked to these conditions, mortality results cannot be interpreted independently of how exposure was applied. Reporting the specific exposure conditions allows researchers to compare responses more meaningfully across experiments involving chemicals, drugs, environmental stressors, or other hazards.
LD50 represents a median lethal level derived from the relationship between exposure and mortality. It identifies an exposure point associated with death in half of the observed population, while lethal-fraction data describe mortality across the exposure range. Researchers can therefore use the full pattern to estimate LD50 and compare the relative toxic effects of different agents or conditions.
Researchers first specify the harmful agent and exposure condition, such as dose, concentration, intensity, or duration. They then observe mortality in the exposed biological population and relate that outcome to the corresponding exposure. Repeating this relationship across exposure levels produces data for examining dose-response behavior, estimating median lethal levels, and assessing population susceptibility.
Lethal fraction is useful when investigators need to characterize mortality caused by chemicals, drugs, environmental stressors, or other biological hazards. The measure supports comparisons of toxic effects and shows how mortality changes under different exposure conditions. It can therefore help organize evidence about the severity of a hazard and the susceptibility of the affected biological population.
The same exposure-response framework can be applied to organisms, cells, or broader populations, allowing researchers to examine differences in susceptibility. Comparing lethal fractions under specified exposure conditions can reveal whether one biological group experiences greater mortality than another. These comparisons are meaningful only when the relevant dose, concentration, intensity, or duration is considered alongside the observed mortality.