Streptomycin belongs to aminoglycoside antibiotics and is a first-line anti-tuberculosis drug. The mutation of the gene encoding the S12 protein of the 30S subunit of Escherichia coli, where it acts, led to resistance to streptomycin in mycobacterium tuberculosis. Resistance mutations in organisms are caused by structural changes at specific sites in the DNA molecule. A drug exists only as a means of isolating a resistant strain, not as an inducer of mutation. When a plate containing a certain concentration of streptomycin is coated with a large number of cell populations, very few cells with streptomycin resistant mutations will grow into colonies on the plate. By further resistance tests, the desired streptomycin resistant strains can be obtained. Drug-resistant mutations are often used as genetic markers, so it is necessary to master the method of isolating streptomycin resistant mutant strains.
Streptomycin has good antibacterial action against Mycobacterium tuberculosis and gram-negative bacteria. The isolation of anti-streptomycin mutants is an important step to study the physiology and pathogenesis of streptomycin. Creative BioMart Microbe provides several services to expedite the isolation of streptomycin resistant mutants.
We have a variety of commercial medium, including incline medium, sporulation medium, seed medium, fermentation medium and indicator medium, which can be used for microbial culture and screening.
We can screen streptomycin-resistant mutants by shaker initial screening and shaker double screening or gradient plate method.
The cup-and-saucer method is commonly used to determine the content of streptomycin in fermentation broth. With the corrected antibacterial zone diameter as the horizontal coordinate and the logarithm of streptomycin concentration as the vertical coordinate, perform linear regression to obtain the linear regression equation.
Figure 1. Evaluation of wild-type rpsL as a counterselectable marker in the streptomycin-resistant strain R. anatipestifer ATCCs (Liu M.; et al. 2019)
The streptomycin resistant mutant strains were screened through the fermentation culture of about F1-F6 generations, and the content of streptomycin in the fermentation broth of each generation strains was detected, and the stable genetic streptomycin resistant high-yielding strains were obtained.
If you are interested in our streptomycin-resistant mutant isolation service, please feel free to contact us.
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