The back-mutation assay method for determining the mutagenicity of various treatments was first developed a little over 50 years ago and has been in continuous use ever since. Shortly after the method was first used it became evident that certain factors of cell density, composition of media, etc., had to be carefully controlled to preserve an acceptable reliability of the method. A factor of particular importance was the suppression of growth of back-mutant prototrophic cells by the large number of auxotrophic cells present, a phenomenon which later became known as the "Grigg Effect." This review describes the origins of the back-mutation method and of the confounding competitive suppression phenomenon, the cause of competitive suppression, methods of diagnosing whether it is likely to bias the interpretation of a particular back-mutation experiment, and an experimental design which removes it entirely as a possible source of error. A number of other phenomena, such as phenotypic lag and coincident mutation associated with back-mutation, are also discussed as possible sources of error.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/s1383-5742(99)00088-5 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Reconstructing early transmission networks of SARS-CoV-2 using a genomic mutation model.
Zool Res
May 2023
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
The coronavirus disease 2019 (COVID-19) pandemic has greatly damaged human society, but the origins and early transmission patterns of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogen remain unclear. Here, we reconstructed the transmission networks of SARS-CoV-2 during the first three and six months since its first report based on ancestor-offspring relationships using BANAL-52-referenced mutations. We explored the position (i.
View Article and Find Full Text PDFA COVID-19 Vaccine for Dogs Prevents Reverse Zoonosis.
Vaccines (Basel)
April 2022
College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea.
COVID-19 is caused by severe acute respiratory syndrome virus type 2 (SARS-CoV-2), which can infect both humans and animals. SARS-CoV-2 originated from bats and can affect various species capable of crossing the species barrier due to active mutation. Although reports on reverse zoonosis (human-to-animal transmission) of SARS-CoV-2 remain limited, reverse zoonosis has been reported in many species such as cats, tigers, minks, etc.
View Article and Find Full Text PDFTabhu: tools for antibody humanization.
Bioinformatics
February 2015
Department of Physics, Sapienza University, Rome 00185, Italy, Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Anker Engelunds Vej 1, 2800 Lyngby, Denmark and Istituto Pasteur-Fondazione Cenci Bolognetti, Rome 00185, Italy Department of Physics, Sapienza University, Rome 00185, Italy, Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Anker Engelunds Vej 1, 2800 Lyngby, Denmark and Istituto Pasteur-Fondazione Cenci Bolognetti, Rome 00185, Italy.
Summary: Antibodies are rapidly becoming essential tools in the clinical practice, given their ability to recognize their cognate antigens with high specificity and affinity, and a high yield at reasonable costs in model animals. Unfortunately, when administered to human patients, xenogeneic antibodies can elicit unwanted and dangerous immunogenic responses. Antibody humanization methods are designed to produce molecules with a better safety profile still maintaining their ability to bind the antigen.
View Article and Find Full Text PDFTracing the origin of 'blue Weimaraner' dogs by molecular genetics.
J Anim Breed Genet
April 2011
Human Genetics, Ruhr-University, Bochum, Germany.
Weimaraner dogs are defined by light brown coat colour termed grey including several shadings ranging from silver and deer to mouse grey. In contrast, the so-called blue Weimaraners (BW) with lightened black-pigmented coat have been proposed to represent spontaneous revertants in the Weimaraner breed. In order to investigate the genetic determinants of the characteristic grey coat colour versus those of BW, known variation in coat colour genes including TYRP1 and MLPH were analysed in a number of grey and blue dogs.
View Article and Find Full Text PDFReturn of chloroquine-susceptible falciparum malaria in Malawi was a reexpansion of diverse susceptible parasites.
J Infect Dis
September 2010
Center for Vaccine Development, University of Maryland School of Medicine, 685 W. Baltimore Street, Baltimore, MD 21201, USA.
The spread of drug-resistant Plasmodium falciparum malaria has been a major impediment to malaria control and threatens prospects for elimination. We recently demonstrated the return of chloroquine-susceptible malaria in Malawi after chloroquine use was abandoned. In this study, we trace the origins of chloroquine-resistant and chloroquine-susceptible parasites in Malawi by sequencing the P.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!