50 µl after Reconstitution
can be aliquoted into 10 x 25 µL for 10 overnight cultures
in 10 mL growth medium for Ames Test in agar plates
Ames tester strain YG7108 and other Ames
tester strains are S. typhimurium and E. coli strains which have been
used for more than 40 years to detect mutagenic compounds in chemicals,
pharmaceuticals, copsmetics, biocides, water and other environmental
samples. They are all listed in the guideline OECD 471:Bacterial Reverse
Mutation Test and in guideline ICH M7 for genotoxic impurities. Point
mutations were made in the histidine (Salmonella typhimurium) or the
tryptophan (Escherichia coli) operon, rendering the bacteria incapable
of producing the corresponding amino acid. These mutations result in
his- or trp- organisms that cannot grow unless histidine or tryptophan
is supplied.
A test sample's mutagenic potential is
assessed by exposing these amino acid-requiring organisms to varying
concentrations of sample and selecting for the reversion event. Media
lacking histidine or tryptophan are used for this selection which allow
only those cells that have undergone the reversion to histidine /
tryptophan prototrophy to survive and grow. A mutagenic event causing
base substitutions or frameshift mutations within the gene may cause a
reversion to amino acid prototrophy. These reverted bacteria will then
grow in histidine- or tryptophan-deficient media, respectively, whereas
non reverted bacteria will not be able to grow. The media during the
growth phase can be liquid or agar based.
YG7108 strains are used in agar based
Ames Test in Petri dish (MacroAmes1), in miniaturized agar based
MicroAmes6 or 24, and in liquid format Ames Test (Ames MPF, Ames II).
Characteristics
- Mutation: hisG46
- Type:Base Pair Substitution
- Target: GGG
- rfa Mutation: defective lipopolysaccharide (LPS) layer
- uvrB Mutation: Eliminates the accurate excision repair mechanism
- Plasmid pYG620 which encodes the E.coli O6-methylguanine DNA Methyltransferase
- Strains are validated for shipment at room temperature from warehouse in Germany or in Switzerland
Safety
In most countries the Ames S.typhimurium
tester strains are categorized under the biosafety level 1 (Risk Group
1, Biological agents that are unlikely to cause human disease). Please
contact your local authorities to verify biosafety level in your own
country.
The host cell Salmonella typhimurium
used in the Ames test system does not contain any genes from other
organisms except for the species Salmonella typhimurium. Strain YG7108
contains E.coli sequences and is considered as GMO. The mutations in the
different Salmonella typhimurium strains were obtained by in vitro
recombination within the species Salmonella typhimurium and in the case
of YG7108 with E.coli. The TA and YG strains have a significantly
reduced lipopolysaccharide layer and are not pathogenic.
Also available
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