Browsing by Author "Ausili, Alessio"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Exploración de la selectividad de colistina hacía Escherichia coli y de daptomicina hacia Staphylococcus aureus mediante espectroscopia infrarroja con transformada de Fourier(Universidad Santiago de Cali, 2023) Gómez Martínez, Andrés; Vélez Bueno, Isaac Eduardo; Oñate Garzón, José Fernando; Ausili, AlessioColistin and daptomycin are clinically important antimicrobial peptides (AMPs) which are bactericidal depending on whether it is a Gram-positive or Gram-negative bacterium; both peptides are characterized by altering the permeability and organization of the cell membrane, therefore, the evaluation of the interaction between both PAMs and E. coli 25922 and S. aureus 25923 cells was carried out, analyzing membrane functional groups by Fourier Transform Infrared Spectroscopy (FTIR). In this work we report band shifts and vibrations in methyl, methylene and phosphate functional groups of the cell membrane in both strains as a consequence of interaction with colistin, unlike daptomycin which only caused representative changes in S. aureus. This establishes FTIR as a tool to explore the activity and selectivity of various PAMs in strains to combat antimicrobial resistanceItem Studies on the interaction of alyteserin 1c peptideand its cationic analogue with model membranes imitating mammalian and bacterial membranes(MDPI AG, 2019-09-25) Aragón-Muriel, Alberto; Ausili, Alessio; Sánchez, Kevin; Rojas A., Oscar E.; Londoño Mosquera, Juan; Polo-Cerón, Dorian; Oñate-Garzón, JoseAntimicrobial peptides (AMPs) are effector molecules of the innate immune system and have been isolated from multiple organisms. Their antimicrobial properties are due to the fact that they interact mainly with the anionic membrane of the microorganisms, permeabilizing it and releasing the cytoplasmic content. Alyteserin 1c (+2), an AMP isolated from Alytes obstetricans and its more cationic and hydrophilic analogue (+5) were synthesized using the solid phase method, in order to study the interaction with model membranes by calorimetric and spectroscopic assays. Differential scanning calorimetry (DSC) showed that both peptides had a strong effect when the membrane contained phosphatidylcholine (PC) alone or was mixed with phosphatidylglycerol (PG), increasing membrane fluidization. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used to study the secondary structure of the peptide. Peptide +2 exhibited a transition from β-sheet/turns to β-sheet/α-helix structures after binding with model membranes, whereas peptide +5 had a transition from aggregation/unordered to β-sheet/α-helix structures after binding with membrane-contained PC. Interestingly, the latter showed a β-sheet structure predominantly in the presence of PG lipids. Additionally, molecular dynamics (MD) results showed that the carboxy-terminal of the peptide +5 has the ability to insert into the surface of the PC/PG membranes, resulting in the increase of the membrane fluidity