In the manual of plasmid pcDNA3.1, they recommend to prepare neomycin in a buffered solution (e.g. 100 mM HEPES, pH 7.3).
is there any other buffered solution can be used?

Moreover, is there any difference between G418 and neomycin? or they are just two names of one chemical?

G418, neomicin, are same chemicals

thank you again:)

Can I solve the G418 in sterilized water? or PBS?

Hi-

Both water and PBS will work fine. You can pretty easily dissolve up to 50mg/ml. I've never tried higher...but don't see why you'd bother.

Good Luck

Dear Annezhu,

G418 is gentamycin, and is NOT the same as neomycin. However, they both belong to the same family of antibiotics called aminoglycosides, which stuff up protein synthesis and hence kill bacteria, or in the case with G418, kills eukaryotes not producing the neomycin-protective protein.

Using a buffered solution like PBS works fine. Standard concentrations are 50-100 mg/ml active antibiotic (stated on the bottle).

G418 is geneticin, not the gentamicin mentionned above.

Fred is correct: Genetecin/G418 is a completely different chemical from gentamycin.

I would only recommend gentamycin as a last resort for removing contamination. Even at low concentrations, many cell culture types do not like it.

As for Geneticin/G418, for many cell culture types with neoR it is more than reasonable to use. It is much stronger than strep/penn, yet it does not effect growth, IME.

-Matt

So do people use G418 as a means to remove contamination or for selection? After reading this topic I was just trying to figure out what all these different chemicals are used for.

Sorry to be a smartass, but above said is only partly correct.

To summarize

Neomycin, Kanamycin, G418 (or Genticin) all belong to a antibiotic group called aminogycosides, they are in fact similar in structure to Gentamycin (B1).

Neomycin, Kanamycin and Gantamycin are kind of specific (in therapeutic dosage) to baterial organelles, so they won't hurt eukaryontic cells, but kill bateria, which makes them a perfect drug to treat infections in animal. All (including g418) block protein synthsis.
G418 or Genticin is related, but has more spefificity for the eukaryontic ribosome (80s subunit) thus will harm or kill cells not engeneered to be resistent (neo-resistenz gene).
This decodes for an enzym called neomycin phosphotransferase and is covalently modifying the amino or hydroxyl functions and thus inhibting the interaction with the ribosome. By the way G418 could be used for bacterial selection too, but then compare prices for kanamycin and G418 and you will understand why your PI would cut your head off, if you would actually use it for bacterial work.

So G418, neomycin, are different things, however, why people usually don't use neomycin but G418 to select eukaryocyte cells?

Thank you~

And another question is that can we use the Ampicilin for medical treatment for bacteria selection?