Analysis Note

Dansyl Labeled Polymyxin B Ready Made Solution is light sensitive. It is recommended to avoid freeze-thaw cycles of PMB-DSL Ready Made Solution. Dansyl Labeled Polymyxin B Ready Made Solution (1.5 mg/mL) can be diluted 1:50 in PBSX1 (Sigma#D8537) to achieve 30 µg/mL final concentration for staining. The above concentration of DSL-PMB was used for E. coli staining see image. Fluorescence Microscopy application: Dansyl Labeled Polymyxin B Ready Made Solution excitation (Ex) wavelength is 330-340nm resulting in emission (Em) range of 540-600nm (λ_max=570nm).

Application

DSL-PMB may have been used: as a fluorescent probe to study polymyxin mode of action and its pharmacokinetics in research and to develop new active derivatives of Polymyxin against multi-drug resistance Gram-negative infections to measure LPS binding affinity by fluorometric displacement assayFluorescent antibiotics can be used for many applications including: Antimicrobial resistance research. Bacterial visualization and imaging. Parent antibiotic mode of action research and new antibiotic discovery. Toxicity studies. Research of bacterial infections and tracking its uptake in vivo.

Biochem/physiol Actions

DSL-PMB′s mode of action is in accordance with Polymyxin B activity. However, MIC assays comparing DSL-PMB, and parent Polymyxin B showed a two to three-fold decrease in bacterial activity. Polymyxin B interacts with anionic lipopolysaccharide (LPS) molecules which are located in Gram-negative bacterial outer membrane. This interaction interferes with the outer membrane′s normal function, causing leakage and enhanced uptake of the antibiotic. The resemblance in properties between Polymyxin B and DSL-PMB allows to fluorescently label Gram-negative bacteria and examine intracellular localization and penetration of Polymyxins in Gram-negative bacteria.

General description

Dansyl Polymyxin B (DSL-PMB) is a fluorescent derivative of Polymyxin B. Polymyxin B is a cationic lipopeptide antibiotic that binds specifically to Gram-negative bacteria. Fluorescent antibiotics are obtained by synthetic conjugation of an antibiotic to a fluorophore.