The Science Journal of the Lander College of Arts and Sciences


Daptomycin is an important lipopeptide antibiotic used in the treatment of systematic and life-threatening infections of the skin and underlying tissue caused by Gram-positive bacteria. Calcium and phosphatidylglycerol (PG) must be present on the target cell membrane for daptomycin’s mechanism of action to proceed. Calcium and PG also promote oligomerization, a formation that has been assumed to aid in the bactericidal process. The purpose of the experiments conducted was to understand the basic biophysical properties of membrane phospholipids as they exist in their pure and mixed monolayer forms. Furthermore, the experiments conducted attempted to discern how daptomycin penetrates the different lipids that were used. Data collected would be useful for future experiments that aim to understand the naturally occurring bacterial membranes and how daptomycin interacts with them. Using precise biophysical approaches, specifically monolayer studies involving a KSV NIMA-Langmuir Trough and Kibron Langmuir Trough, our lab conducted basic research which could prove to be useful in revealing daptomycin’s ambiguity. Preliminary results revealed differences in isotherms between phospholipids with anionic and zwitterionic head-groups. Further data collected revealed daptomycin’s degree of insertion in phospholipids with and without the presentation of calcium. Given the limitations of our retrospective studies, additional studies are needed to make definitive evaluations with these results. Because resistance to daptomycin is rising, it is particularly imperative to conduct further research to understand its unsolved mechanism of action.



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