| Description: |
The penicillin-streptomycin solution is the most commonly used antibiotic to prevent microbial contamination in vitro. Penicillin interferes with the synthesis of bacterial cell walls, particularly in Gram-positive bacteria. Streptomycin binds to the 30S subunit of bacterial ribosomes, inhibiting protein synthesis and being effective against both Gram-negative and Gram-positive bacteria, especially Gram-negative ones. Amphotericin B binds to ergosterol in fungal cell membranes, causing membrane damage, increased permeability, leakage of intracellular contents, disruption of normal metabolism, and a fungistatic effect, but it has no effect on bacteria. The combined use of penicillin, streptomycin, and amphotericin B can prevent most bacterial and fungal contamination.
Penicillin is sensitive to temperature and pH, degrades easily at room temperature, and requires cryopreservation, with its stability being optimal at pH 6.0-6.5. Streptomycin is relatively stable, with optimal stability at pH 5.0-7.5. Amphotericin B is unstable at room temperature and is easily degraded by light, heat, and acid, with its strongest antifungal effect at pH 6.0-7.5. |
