|
Antibiotic
|
Mode of Action |
Resistance Mechanism |
Working Concentration |
Stock Solution |
|
Ampicillin
(Amp)
|
A derivative of penicillin that kills growing cells by interfering with
bacterial cell wall synthesis. |
The resistance gene (bla) specifies a periplasmic enzyme, β-lactamase,
which cleaves the β-lactam ring of the antibiotic. |
50–125μg/ml in water |
50mg/ml |
|
Chloramphenicol
(Cm) |
A bacteriostatic agent that interferes with bacterial protein synthesis by
binding to the 50S subunit of ribosomes and preventing peptide bond formation. |
The resistance gene (caf) specifies an acetyltransferase that acetylates,
and thereby inactivates the antibiotic. |
20–170μg/ml in ethanol |
34mg/ml |
|
Kanamycin
(Kan) |
A bactericidal agent that binds to 70S ribosomes and causes misreading of
the messenger RNA. |
The resistance gene (kan) specifieds an enzyme (aminoglycoside
phosphotransferase) that modifies the antibiotic and prevents its interaction
with ribosomes. |
30μg/ml in water |
50mg/ml |
|
Streptomycin
(Sm) |
A bactericidal agent that binds to the 30S subunit of ribosomes and causes
misreading of the messenger RNA. |
The resistance gene (str) specifies an enzyme that modifies the
antibiotic and inhibits its binding to the ribosome. |
30μg/ml in water |
50mg/ml |
|
Tetracycline
(Tet) |
A light-sensitive bacteriostatic agent that prevents bacterial protein
synthesis by binding to the 30S subunit of ribosomes. |
The resistance gene (tet) sepcifies a protein that modifies the bacterial
membrane and prevents transport of the antibiotic into the cell. |
10μg/ml in liquid culture; 12.5μg/ml in plates |
12.5mg/ml in ethanol |
|
Neomycin
(Neo) |
A bactericidal agent that blocks protein synthesis by binding to the
prokaryotic 70S ribosomal subunit. High concentrations of neomycin can
result in toxicity to eukaryotic cells because it can interact with
mitochondrial ribosomes, which are similar to prokaryotic ribosomes, and
with reduced affinity, other eukaryotic ribosomes. |
Expression of the bacterial APH (aminoglycoside phosphotransferase) gene
(derived from Tn5). |
50μg/ml for bacterial selection |
25mg/ml in water |
|
Hygromycin
(Hygro) |
A protein synthesis inhibitor that interferes with 80S ribosome
translocation and causes mistranslation. |
The resistance gene (hph) specifies a phosphotransferase that
catalyzes the phosphorylation of the 4-hydroxyl group on the cyclitol ring (hyosamine),
thereby producing 7'-O-phosphoryl-hygromycin B, which lacks biological
activity both in vivo and in vitro. |
50–1,000μg/ml for mammalian selection; 20–200μg/ml for bacterial selection |
100mg/ml in HEPES buffer
(pH 7.0) or water |
|
Puromycin
(Puro) |
An aminonucleoside antibiotic that blocks protein synthesis by specifically
inhibiting peptidyl transfer on both prokaryotic and eukaryotic ribosomes
causing premature chain termination. |
The resistance gene (pac) encodes puromycin N-acetyl-transferase. |
1–10μg/ml for mammalian selection |
10mg/ml in HEPES buffer
(pH 7.0) or water |
|
|
G418 |
Binds to the 80S ribosomal subunit found only in eukaryotes and blocks
protein synthesis. |
Expression of the bacterial APH (aminoglycoside phosphotrasferase) gene
(derived from Tn5) in eukaryotic cells results in detoxification of G418. |
G418 is often used for initial selection at 500μg/ml, with a range of 50–1,000μg/ml |
50mg/ml in either water or 100mM HEPES (pH 7.3) prepared in a highly
buffered solution to maintain tissue culture media pH |
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