Effect of Arginine-based Surfactant on Model Membranes of Bacteria and Mammalian Virus

SABATIE, ALEJANDRO ENRIQUE; HERMET, MELISA; FAIT, MARÍA E.; MORCELLE, SUSANA R.; FANANI, MARÍA LAURA

Córdoba, Córdoba

Congreso; LI Reunión Anual de la Sociedad Argentina de Biofísicos 2023; 2023

Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), CONICET ? Universidad Nacional de Córdoba

Arginine-based surfactants, as cationic amphiphiles, have an intrinsic biocidal activityagainst viruses, bacteria and fungi. We have synthesized in our laboratory an argininealkyl-amide (ArgC12) which has been characterized as a broad spectrum antimicrobialagent. The biocidal mechanism described for this kind of compounds involves itsinteraction with the cytoplasmic membrane. The aim of this work was to deepen into thismechanism using in vitro model membranes.Liposomes were prepared using an E. coli lipid extract (ECEx) and a mammalian-like lipidmixture (POPC/16:0 SM/Cho 1:1:1, MVM) for bacterial and enveloped mammalian-likevirus membrane models respectively. ArgC12 was a stronger inducer of the contentleakage of MVM liposomes, measured as the release of carboxyfluorescein (CF50% of 79.3and 289.7 μM for MVM and ECEx, respectively), evidencing a differential interaction ineach case. Our compound also induced membrane fusion, which may be related to theneutralization of surface charges. Additionally, MVM liposomes evidenced membranedisruption at high surfactant concentrations. Fluorescence studies also suggested that thestructure of the membrane bound water and the membrane microviscosity were alteredupon ArgC12 insertion, with saturation at a lipid/surfactant ratio of 1:3.On the other hand, penetration of ArgC12 into the model lipid monolayers indicated thatthe surfactant could be incorporated in both membranes to a similar extent, whichsuggested that the differences found in the surfactant-treated liposomes are not aconsequence of differential amphiphile’s incorporation.Finally, we found that after the insertion of ArgC12 into the ECEx monolayers themembrane became less compressible and more surface-unstable. Contrarily, when thesurfactant was inserted into the MVM monolayers, it induced a more compressible andstable membrane. This finding may be related to the differential resistance of both lipidmembranes to ArgC12-induced content leakage.