G418
Encyclopedia
G418 is an aminoglycoside
antibiotic
similar in structure to gentamicin B1. It is produced by Micromonospora rhodorangea. G418 blocks polypeptide synthesis by inhibiting the elongation step in both prokaryotic and eukaryotic cells. Resistance to G418 is conferred by the neo gene from Tn5 encoding an aminoglycoside 3‘-phosphotransferase, APH 3‘ II. G418 is commonly used in laboratory research to select genetically engineered cells (typically using the KanMX selectable marker). In general for bacteria and algae concentrations of 5 mg/L or less are used, for mammalian cells concentrations of approximately 400 mg/L are used for selection and 200 mg/L for maintenance. However, optimal concentration for resistant clones selection in mammalian cells depends on the cell line used as well as on the plasmid
carrying the resistance gene, therefore antibiotic titration should be done to find the best condition for every experimental system. Titration should be done using antibiotic concentrations ranging from 100 mg/L up to 1400 mg/L. Resistant clones selection could require from 1 to up to 3 weeks.
G418 is soluble in water (50 mg/ml).
for sensitive cells (like NIH 3T3) and the highest LD50
(can be up to 5,000 μg/ml) for resistant cells (NIH 3T3 transfected with resistant genes). Gentamycins have almost no selectivity, except Gentamycin X2 .
Information from G418-evopure.com
Aminoglycoside
An aminoglycoside is a molecule or a portion of a molecule composed of amino-modifiedsugars.Several aminoglycosides function as antibiotics that are effective against certain types of bacteria...
antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
similar in structure to gentamicin B1. It is produced by Micromonospora rhodorangea. G418 blocks polypeptide synthesis by inhibiting the elongation step in both prokaryotic and eukaryotic cells. Resistance to G418 is conferred by the neo gene from Tn5 encoding an aminoglycoside 3‘-phosphotransferase, APH 3‘ II. G418 is commonly used in laboratory research to select genetically engineered cells (typically using the KanMX selectable marker). In general for bacteria and algae concentrations of 5 mg/L or less are used, for mammalian cells concentrations of approximately 400 mg/L are used for selection and 200 mg/L for maintenance. However, optimal concentration for resistant clones selection in mammalian cells depends on the cell line used as well as on the plasmid
Plasmid
In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular...
carrying the resistance gene, therefore antibiotic titration should be done to find the best condition for every experimental system. Titration should be done using antibiotic concentrations ranging from 100 mg/L up to 1400 mg/L. Resistant clones selection could require from 1 to up to 3 weeks.
G418 is soluble in water (50 mg/ml).
G418 impurity profile
G418 is produced by fermentation and isolation processes and the G418 producing strain Micromonospora rhodorangea produces many other gentamycins while produing G418. The common impurities of G418 is Gentamycin X2, gentamicin A, gentamycin C1, C2, C1a and C2a. The quality of G418 shall not be based on just the potency, but more on the selectivity defined by the killing curve of the sensitive cells vs the resistant cells. A good G418 product shall have lowest LD50LD50
In toxicology, the median lethal dose, LD50 , LC50 or LCt50 of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration...
for sensitive cells (like NIH 3T3) and the highest LD50
LD50
In toxicology, the median lethal dose, LD50 , LC50 or LCt50 of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration...
(can be up to 5,000 μg/ml) for resistant cells (NIH 3T3 transfected with resistant genes). Gentamycins have almost no selectivity, except Gentamycin X2 .
Information from G418-evopure.com