Canavanine resistance

McDougall, K.J. Lemontt. J.F. (1979) Effects of spermine on the detection of induced forward mutation at the can locus in yeast evidence for selection against canavanine-resistant mutants. Mutat. Res.. 63. 21-34... 

Yang, W., Urano, J., and Tamanoi, F. (2000). Protein farnesylation is critical for maintaining normal cell morphology and canavanine resistance in Schizosaccharomyces pombe. J Biol Chem 275 429-438. 

Resistance to End Product Repression, a) Antimetabolites. The use of toxic antimetabolites to select resistant cultures often yields mutants whose normal biosynthetic pathway enzymes are not repressed by the end product. For example, trifluoreoleucine selects mutants with derepressed levels (as much as 10-fold) of leucine biosynthetic enzymes (Calvo and Calvo, 1967). Certain canavanine-resistant mutants produce 30 times more of the arginine pathway enzymes than do their sensitive parents (Jacoby and Gorini, 1967). Mutants of Lactobacillus casei resistant to dichloroamethopterin are derepressed 80-fold in their ability to form thymidylate synthetase (Crusberg and Kisliuk, 1969). When Diplococcus pneumoniae mutants are selected on the basis of resistance to amethopterin, these cultures produce 100 times as much dihydrofolate reductase as the parent culture (Sirotnak et al, 1969). 

Morfaux, J.N. and Dupuy, P. (1966). Comparaison de 1 exsorption des addes amines par une souche de Saccharomyces cerevisiae et un mutant resistant a la canavanine. C. R. Biologies, 263,1224. 

The generalist feeding insect Heliothis virescens, the tobacco budworm, has relatively high resistance to canavanine but not to a number of other nonprotein amino acids (Berge et al., 1986). In this case, canavanine (37) was shown to be neither excreted nor sequestered, but rather metabolized by the insect. In Caryedes brasiliensis, Sternechus tuberculatus... 

After mutation, there is a phase of mutation expression. Mutation expression is very relevant in systems based on the induction of resistance mutation. Resistance at the permease level can be expressed only after functional permeases have been diluted out of the membrane this applies to canavanine or other types of analogue systems. 

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