Membrane Lysis Research Articles

Model self-assembling arginine-based tripeptides show selective activity against Pseudomonas bacteria.

Three model arginine-rich tripeptides RXR (X = W, F or non-natural residue 2-napthylalanine) were investigated as antimicrobial agents, with a specific focus to target Pseudomonas aeruginosa through membrane lysis. Activity against biofilms was related to binding of the second messenger molecule, nucleotide bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). Strong selective activity against P. aeruginosa in planktonic form was observed for RFR and RWR.

Acylation of the antimicrobial peptide CAMEL for cancer gene therapy

Obtaining ideal gene delivery vectors is still a major goal in cancer gene therapy. CAMEL, a short hybrid antimicrobial peptide, can kill cancer cells by membrane lysis. In this study, we constructed a series of non-viral vectors by attaching fatty acids with different chain lengths to the N-terminus of CAMEL. Our results showed that the cellular uptake and transfection efficiency of acyl-CAMEL started to significantly increase from a chain length of 12 carbons. C18-CAMEL was screened for gene delivery because it had the highest transfection efficiency. Surprisingly, C18-CAMEL/plasmid complexes displayed strong endosomal escape activity after entering cells via endocytosis. Importantly, C18-CAMEL could deliver p53 plasmids to cancer cells and significantly inhibited cell proliferation by the expression of p53. In addition, the C18-CAMEL/p53 plasmid complexes and the MDM2 inhibitor nutlin-3a showed significantly synergistic anticancer activity against MCF-7 cells expressing wild-type p53. Conclusively, our study demonstrated that conjugation of stearic acid to antimicrobial peptides is a simple and successful approach for constructing efficient and economical non-viral vectors for cancer gene therapy.

Differential Fractionation of Erythrocytes Infected by Plasmodium berghei.

The study of host/pathogen interactions at the cellular level during Plasmodium intra-erythrocytic cycle requires differential extraction techniques aiming to analyze the different compartments of the infected cell. Various protocols have been proposed in the literature to study specific compartments and/or membranes in the infected erythrocyte. The task remains delicate despite the use of enzymes or detergents theoretically capable of degrading specific membranes inside the infected cell. The remit of this protocol is to propose a method to isolate the erythrocyte cytosol and ghosts from the other compartments of the infected cell via a percoll gradient. Also, the lysis of the erythrocyte membrane is done using equinatoxin II, which has proven to be more effective at erythrocyte lysis regardless of the cell infection status, compared to the commonly used streptolysin. The parasitophorous vacuole (PV) content is collected after saponin lysis, before recovering membrane and parasite cytosol proteins by Triton X-100 lysis. The lysates thus obtained are analyzed by Western blot to assess the accuracy of the various extraction steps. This protocol allows the separation of the host compartment from the parasite compartments (PV and parasite), leading to potential studies of host proteins as well as parasite proteins exported to the host cell.

Effect of quercitin impregnated silver nanoparticle on growth of some clinical pathogens

Quercetin as a bioflavonoid is commonly used in pharmaceutical industry to treat various diseases. The drug delivery system of these quercetin biomolecules is being limited by its poor water solubility, absorption, and permeability. Silver nanoparticle plays a vital role in development of new antimicrobial drugs against many pathogenic microorganisms. In the present investigation, the solubility of quercitin was first performed in methanolic extract and their spherical silver nanoparticles (AgNPs) with uniform distribution were synthesized with average size of 49 nm. The antimicrobial activity of standard quercetin and their silver nanoparticles were tested against some pathogenic strains using agar well diffusion methodology. The standard quercetin (Ef) had shown slight zone of inhibition against Klebsiella pneumoniae(ATCC 790603), Enterococcus faecalis (ATCC 51299), Proteus vulgaris (ATCC 426), Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 4330), Pseudomonas aeruginosa (ATCC 27853) strain which might be because of its poor water solubility behavior. The impreganation of quercetin with silver nanoparticles showed their greater zone of inhibition against these pathogenic strains which confirmed the enhancement of their antimicrobial properties. The enhancement of antimicrobial activity might be due to effectively lysis of cell membrane after absorption of nano-sized particle of silver nanoparticles.

Human GBP1 Differentially Targets <i>Salmonella</i> and <i>Toxoplasma</i> to License Recognition of Microbial Ligands and Caspase-Mediated Death

Interferon-inducible Guanylate binding proteins (GBPs) promote cell-intrinsic defense through host cell death. GBPs target pathogens and pathogen-containing vacuoles, and assist in membrane-disruption for release of microbial molecules that trigger inflammasome activation. GBP1 mediates atypical macrophage apoptosis or pyroptosis infected with Toxoplasma gondii or Salmonella Typhimurium, respectively. The pathogen-proximal detection-mechanisms of GBP1 are poorly understood, since humans lack functional Immunity-related GTPases (IRGs) which control mGbps in mice. Here, we describe two new assays showing that GBP1 promotes lysis of Tg-containing vacuoles and parasite plasma membranes, releasing Tg-DNA. In contrast, we show GBP1 targets cytosolic STm, recruits caspase-4 to the bacterial surface for its activation by LPS but does not contribute to bacterial vacuole escape. During STm infection, caspase-1 cleaves and inactivates GBP1, and expression of cleavage-deficient GBP1D192E mutant increased pyroptosis through absence of feedback inhibition. Our studies elucidate microbe-specific roles of GBP1 in infection-detection triggering assembly of divergent caspase signaling platforms.

A Review for Antimicrobial Peptides with Anticancer Properties: Re-purposing of Potential Anticancer Agents

Abstract In recent years, various research on cancer treatment has achieved significant progress. However, some of these treatments remain disputable because of the emergence and development of drug resistance, and the toxic side effects that were brought about by the lack of selectivity displayed by the treatments. Hence, there is considerable interest in a new class of anticancer molecules that is currently still under investigation termed the cationic antimicrobial peptides (AMPs). AMPs are a group of pervasive components of the innate immunity which can be found throughout all classes of life. The small innate peptides cover a broad spectrum of antibacterial activities due to their electrostatic interactions with the negatively charged bacterial membrane. Compared with normal cells, cancer cells have increased proportions of negatively charged molecules, including phosphatidylserine, glycoproteins, and glycolipids, on the outer plasma membrane. This provides an opportunity for exploiting the interaction between AMPs and negatively charged cell membranes in developing unconventional anticancer strategies. Some AMPs may also be categorized into a group of potential anticancer agents called cationic anticancer peptides (ACPs) due to their relative selectivity in cell membrane penetration and lysis, which is similar to their interaction with bacterial membranes. Several examples of ACPs that are used in tumor therapy for their ability in penetrating or lysing tumor cell membrane will be reviewed in this paper, along with a discussion on the recent advances and challenges in the application of ACPs.

Resveratrol, curcumin and gallic acid attenuate glyoxal-induced damage to rat renal cells

Glyoxal (GO), a by-product of glucose auto-oxidation, is involved in the glycation of proteins/ lipids and formation of advanced glycation (AGE) and lipoxidation (ALE) end products. AGE/ALE were shown to contribute to diabetic complications development/progression such as nephropathy. Diabetic nephropathy progression has an oxidative nature. Given the antioxidant effects of polyphenols, potential protective effects of resveratrol, curcumin and gallic acid, in rat renal cells treated with GO, were evaluated in the present work. According to our results, incubation of GO with the cells reduced their viability and led to membrane lysis, reactive oxygen species (ROS) formation, lipid peroxidation, mitochondrial membrane potential collapse, and lysosomal membrane leakage. These findings were prevented by pre-treatment with resveratrol, curcumin and gallic acid. Mitochondrial and lysosomal toxic interactions appear to worsen oxidative stress/cytotoxicity produced by GO. Resveratrol, curcumin and gallic acid inhibited ROS formation and attenuated GO-induced renal cell death.

IN VITRO EVALUATION OF ANTI INFLAMMATORY ACTIVITY OF METHANOLIC AND ETHANOLIC LEAF EXTRACT OF PSIDIUM GUAJAVA

The objective of the current research work was to determine the anti inflammatory activity of Psidium guajava by the Human Red Blood Cell membranes stabilization method. The methanol and ethanol leaf extract of plant Psidium guajava were investigated for their invitro anti-inflammatory property by Human red blood cell membrane stabilization method. The prevention of hypotonocity induced HRBC membrane lysis was taken as a measure of a anti-inflammatory activity. The anti inflammatory activity of methanol and ethanol leaf extract of psidium guajava were compared to that of standard drug Diclofenac.

PHYTOCHEMICAL SCREENING AND INVITRO ANTI-INFLAMATORY ACTIVITY OF ETHANOLIC EXTRACT OF CENTELLA ASIATICA

In ayurvedic medicine Centella asiatica is a valuable medicinal herbaceous creeper which has been valued for hundreds of years. Phytochemical analysis of Centella asiatica (Apiaceae) plant extracts revealed the presence of varied biochemical compounds like alkaloids, flavonoids, glycosides, phenolic compounds, triterpenoids and saponin etc. Since phenolic compounds, triterpenoids and flavonoids have remarkable anti-inflammatory, anti-arthritic and antioxidant activities, so our present work aims at evaluating the in vitro anti-inflammatory activity by Human Red Blood Cell (HRBC) membrane stabilization. To measure the anti-inflammatory activity, the inhibition of hypotonicity induced HRBC membrane lysis was used. The percentage Haemolysis was experimented from concentration of 50µg/ml to 2000µg/ml and the values reduced from 32.25% to 5.02%, on the other hand percentage Stabilisation in the same concentration range increased from 67.74% to 94.97%. Diclofenac sodium was used as the standard drug and the same experiment conducted in the same concentration range and the values of percentage haemolysis reduced from 47.18% to 1.24% and the percentage stabilisation increased from 52.81% to 98.76%. The results show that the extracts of Centella asiatica exhibited anti-inflammatory activities. Centella asiatica may be a profusely branched prostate herb consisting of active principles like Vallarine, Asiaticoside, Sitosterol, Tannins, Oxy asiaticoside. Asiaticoside is used in the treatment of leprosy. Sitosterol and tannin possess antiprotozoal and spasmolytic property. According to Siddha literature, the leaves of Centella asiatica are used for the treatment of syphilis, elephantiasis, all kinds of fever, abdominal disorder of children and hydrocele and these features are highlighted in this article.

Comparison of Walnut (Juglans regia L.) and Olive (Olea europaea L.) Leaves in Terms of Antioxidant and Antiinflammatory Activity

Walnut and olive are consumed by people as food for many years. It is seen that not only fruits but also leaves are used among the people. In this study, walnut and olive leaves were compared in terms of antioxidant and anti-inflammatory capacity. DPPH • and ABTS •+ free radical scavenging activity methods were used for determination antioxidant capacity. For an in vitro measure of anti-inflammatory activity, stabilization of human red blood cell membrane by heat induced membrane lysis was done. The results showed that walnut leaf extract had the highest antioxidant and anti-inflammatory activity with IC50 values of 0.0530 mg mL -1 for DPPH radical scavenging activity; 0.0421mg mL -1 for ABTS radical scavenging activity and 0.3959 mg mL -1 for human red blood cell membrane stabilization capacity. It is thought that the difference in the activity levels of extracts may be owing to the several types and amounts of polyphenolic compounds.

Bactericidal Effect of Clove Oil against Multidrug-Resistant Streptococcus suis Isolated from Human Patients and Slaughtered Pigs.

Streptococcus suis is a zoonotic pathogen that is currently considered an emerging multidrug-resistant (MDR). Increasing antibiotic resistance can lead to the unsuccessful treatment of S. suis infection. Recently, many investigations of medicinal plants were conducted for the treatment of infection as a result of the increase of antibiotic-resistant bacteria. The aims of this study were to determine the chemical composition of essential oil from Syzygium aromaticum (L.) Merr. & L.M. Perry and the antibacterial activities of clove oil on MDR S. suis. Using gas chromatography coupled to a mass spectrometer, eugenol (97.76%) was found to be the major active ingredient of clove oil. In vitro antibacterial activities of clove oil against MDR S. suis were evaluated. Using the agar disc diffusion test, the clove oil showed a maximum zone of inhibition at 15% (v/v) oil concentration. In a broth microdilution method, the minimum bactericidal concentration of clove oil against all MDR S. suis isolates was 0.1% (v/v). A time-kill analysis was performed, and the killing kinetics of clove oil showed that MDR S. suis was completely reduced after 15 min of exposure to clove oil. In addition, clove oil exhibited a strong antibacterial activity at all pH values applied following incubation of MDR S. suis in pH-adjusted media with clove oil. Moreover, scanning electron microscopy revealed the nonviable S. suis isolates clearly showed atypical form and cell membrane lysis after incubation with clove oil. This study confirms the efficacy of clove oil as a natural antimicrobial against MDR S. suis and suggests the possibility of employing it as a promising alternative product for control of infectious diseases caused by S. suis in animal and human patients.

Nanoclay-induced bacterial flocculation for infection confinement

Effects of size and charge of anionic nanoclays on their interactions with bacteria-mimicking lipid membranes, bacterial lipopolysaccharide (LPS), and Gram-negative bacteria were investigated using ellipsometry, dynamic light scattering, ζ-potential measurements, and confocal microscopy combined with Live/Dead staining. Based on particle size and charge density, three different anionic hectorite nanoclays were employed, and investigated in the presence and absence of the net cationic human antimicrobial peptide LL-37 (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES). In the absence of this peptide, the nanoclays were found not to bind to similarly anionic bacteria-mimicking model phospholipid membranes, nor to destabilize these. Similarly, while all nanoclays induced aggregation of Escherichia coli bacteria, the flocculated bacteria remained alive after aggregation. In contrast, LL-37 alone, i.e. in the absence of nanoclay particles, displays antimicrobial properties through membrane lysis, but does not cause bacterial aggregation in the concentration range investigated. After loading the nanoclays with LL-37, potent bacterial aggregation combined with bacterial membrane lysis was observed for all nanoclay sizes and charge densities. Demonstrating the potential of these combined systems for confinement of infection, LPS-induced NF-κB activation in human monocytes was found to be strongly suppressed after nanoclay-mediated aggregation, with a wide tolerance for nanoparticle size and charge density.

Distinct Kinetics in Electrophoretic Extraction of Cytoplasmic RNA from Single Cells.

The physical fractionation of cytoplasmic versus nuclear components of cells is a key step for studying the subcellular localization of molecules. The application of an electric field is an emerging method for subcellular fractionation of proteins and nucleic acids from single cells. However, the multibiophysical process that involves electrical lysis of cytoplasmic membranes, electrophoresis, and diffusion of charged molecules remains unclear. Here we study RNA dynamics in single cells during the electrophoretic extraction via a microfluidic system that enables stringent fractionation of the subcellular components leveraging a focused electric field. We identified two distinct kinetics in the extraction of RNA molecules, which were respectively associated with soluble RNA and mitochondrial RNA. We show that the extraction kinetics of soluble RNA is dominated by electrophoresis over diffusion and has a time constant of 0.15 s. Interestingly, the extraction of mitochondrial RNA showed unexpected heterogeneity in the extraction with slower kinetics (3.8 s), whilereproducibly resulting in the extraction of 98.9% ± 2% after 40 s. Together, we uncover that the microfluidic system uniquely offers length bias-free fractionation of RNA molecules for quantitative analysis of correlations among subcellular compartments by exploiting the homogeneous electrophoretic properties of RNA.

Field Evaluation of Some Insecticides for Controlling Black cutworm, Agrotis ypsilon and Their Effect on Some Histological Aspects.

Field experiments were carried out to evaluate the efficacy of certain insecticides, Lambada cyhalothrin (5% EC) as Affact power, Lambada cyhalothrin (10.6%) + Thiamethoxan (14.1%) as Anjio (24.7% SC) and Chlorantraniliprole formulated as Coragen (20% SC) belonging to different groups against Agrotis ypsilon larvae in potato crop in Egyptian governorate; El Qalyubia during two successive seasons, February 2018 and 2019 under field conditions. All the tested plots showed a highly significant reduction in Agrotis ypsilon population after 3 days post-treatment with all tested insecticides as poison baits. The reduction was higher in the second season 2019 than the first season 2018 with Coragen and Affact power. The most effective insecticides by the mean of reduction % in the two seasons were Coragen and Anjio by 92.91 and 92.26%, respectively while Affact power by 88.68%. Semi-field technique was used to study the histological changes of two sub-lethal rates 50 and 25% of these compounds on the 4th and 5th instars midgut structure post three days of treatments. The midgut structure was affected with all the treated rates of insecticides with various degrees that concluded in separation or disappearing and lysis of basement membrane which led to separate the epithelial cells from it with undistinguished shapes. The peritrophic membrane was separated or destructed and lysis led to mixing of the lumen content with lysis cells. All or some of these changes led to the loss of the midgut function, nutrition, and digestion; so they could be used in the integrated pest management control against Agrotis ypsilon

Antioxidant, anti-inflammatory and antiarthritic potential of Moringa oleifera Lam: An ethnomedicinal plant of Moringaceae family

Medicinal plants are increasingly being evaluated for the treatment of chronic disorders. This study was aimed at assessing anti-arthritic potential of Moringa oleifera (wild type). Different extracts of the plant leaves were prepared and evaluated for the presence and quantification of phytochemicals. The plant extracts were assessed for in vitro antioxidant activity by different methods followed by in vitro anti-inflammatory assays such as protein denaturation, membrane stabilization and anti-proteinase activities. The plant extracts were further assessed in Wistar rats by formaldehyde induced arthritis model at 150, 300 and 600 mg/kg dosage level. Chemical analysis showed that methanolic and aqueous extracts contained the highest total phenolic and flavonoid contents. Kaempferol, gallic acid, vanillic acid, coumaric acid and quercetin were detected and quantified in the plant extracts. It was found that the methanolic, aqueous and ethyl acetate extracts had exhibited the maximum in vitro antioxidant potential. These extracts also exhibited a decrease in protein denaturation, prevented lysis of red blood cell membranes and showed anti-proteinase activities. These extracts showed significant inhibition in paw inflammation and prevented arthritis induced anemia and weight loss in rats in dose dependent manner. The outcomes of this research indicated that all extracts of M. oleifera had exerted significant antioxidant and anti-arthritic potential in rats in dose dependent manner. Anti-arthritic activity of M. oleifera might be due to the scavenging of free radicals, inhibition of protein denaturation, membrane stabilization and anti-proteinase activity.

Lytic peptide-grafted beta-cyclodextrin polymer based nano-scaled drug delivery system with enhanced camptothecin anti-cancer efficacy

The aqueous solubility of drug molecules is closely related to its bioactivity like bioavailability and subsequent therapeutic index, especially in the case of hydrophobic drugs like camptothecin (CPT), a potential broad-spectrum anti-cancer agent. Enhanced anti-cancer activity and selectivity of CPT are equally important. Inspired by host-guest effect and drug combination regimen, we developed a novel tumor lytic peptide incorporated drug delivery system by forming beta-cyclodextrin polymer (BCDp) based inclusion complex in nano-scaled size. In this study, BCDp formed inclusion complex with CPT and then a lytic-type peptide (ZH) was grafted. The resulting combinational formulation of BCDp, CPT and ZH, named as ZH-BCDp-CPT inclusion complex, demonstrated greater solubility resulting from its nano-scaled size, amorphous solid state and inclusion structure. Moreover, ZH facilitated quick internalization of conjugated drug via cell membrane lysis, leading to efficient intracellular drug delivery. This novel drug formulation was featured with prolonged circulation, enhanced anti-cancer efficacy, selectivity, anti-cell migration activity and better biocompatibility in comparison with crude CPT and binary BCDp-CPT inclusion complex, all of which were attributed to a cooperative action between ZH and BCDp-CPT inclusion complex. Our results suggested ZH-BCDp-CPT inclusion complex induced cell apoptosis by up-regulation of Bax and P53 and down-regulation of Bcl-2, primarily involved in the mitochondrial pathways.

Missiles of Mass Disruption: Composition and Glandular Origin of Venom Used as a Projectile Defensive Weapon by the Assassin Bug Platymeris rhadamanthus.

Assassin bugs (Reduviidae) produce venoms that are insecticidal, and which induce pain in predators, but the composition and function of their individual venom components is poorly understood. We report findings on the venom system of the red-spotted assassin bug Platymeris rhadamanthus, a large species of African origin that is unique in propelling venom as a projectile weapon when threatened. We performed RNA sequencing experiments on venom glands (separate transcriptomes of the posterior main gland, PMG, and the anterior main gland, AMG), and proteomic experiments on venom that was either defensively propelled or collected from the proboscis in response to electrostimulation. We resolved a venom proteome comprising 166 polypeptides. Both defensively propelled venom and most venom samples collected in response to electrostimulation show a protein profile similar to the predicted secretory products of the PMG, with a smaller contribution from the AMG. Pooled venom samples induce calcium influx via membrane lysis when applied to mammalian neuronal cells, consistent with their ability to cause pain when propelled into the eyes or mucus membranes of potential predators. The same venom induces rapid paralysis and death when injected into fruit flies. These data suggest that the cytolytic, insecticidal venom used by reduviids to capture prey is also a highly effective defensive weapon when propelled at predators.

Antibacterial Nanocomposites Based on Thermosetting Polymers Derived from Vegetable Oils and Metal Oxide Nanoparticles.

Thermosetting polymers derived from vegetable oils (VOs) exhibit a wide range of outstanding properties that make them suitable for coatings, paints, adhesives, food packaging, and other industrial appliances. In addition, some of them show remarkable antimicrobial activity. Nonetheless, the antibacterial properties of these materials can be significantly improved via incorporation of very small amounts of metal oxide nanoparticles (MO-NPs) such as TiO2, ZnO, CuO, or Fe3O4. The antimicrobial efficiency of these NPs correlates with their structural properties like size, shape, and mainly on their concentration and degree of functionalization. Owing to their nanoscale dimensions, high specific surface area and tailorable surface chemistry, MO-NPs can discriminate bacterial cells from mammalian ones, offering long-term antibacterial action. MO-NPs provoke bacterial toxicity through generation of reactive oxygen species (ROS) that can target physical structures, metabolic paths, as well as DNA synthesis, thereby leading to cell decease. Furthermore, other modes of action—including lipid peroxidation, cell membrane lysis, redox reactions at the NP–cell interface, bacterial phagocytosis, etc.—have been reported. In this work, a brief description of current literature on the antimicrobial effect of VO-based thermosetting polymers incorporating MO-NPs is provided. Specifically, the preparation of the nanocomposites, their morphology, and antibacterial properties are comparatively discussed. A critical analysis of the current state-of-art on these nanomaterials improves our understanding to overcome antibiotic resistance and offers alternatives to struggle bacterial infections in public places.

Identification of therapeutic peptide scaffold from tritrpticin family for urinary tract infections using in silico techniques

Antimicrobial peptides (AMPs) like tritrpticins, exhibit non-specific membrane lysis of gram-negative bacteria and can replace antibiotics, combating multi-drug resistance observed in UTI patients. Tritrpticins designated – NT, T1, T2, T3, T5, T7 and T8, were computationally investigated by interaction with Escherichia coli membrane model, mammalian cell toxicity and structural stability to identify a potential drug scaffold for UTI. Initially T3 was eliminated due to low interaction with Escherichia coli membrane model, based on its computed solvation energy. Further, negative support vector machine (SVM) scores revealed non-toxicity of T1, T2, T5, T7 and T8. Finally, at 310 K and varying pH 4.5–9.0, T5 exhibited highest structural stability based on its highest consistency of hydrogen bonds (H-bonds), root mean square deviation (RMSD) and secondary structure profiles along with its lowest conformational free energy. Overall, T5 could be considered a promising peptide drug scaffold to combat UTI.ABBREVIATIONSAMPantimicrobial peptidePBEQPoisson Boltzmann equationH-bondshydrogen bondsMICminimum inhibitory concentrationLD50lethal dose, 50%RMSDroot mean square deviationSVMsupport vector machineUTIurinary tract infectionCommunicated by Ramaswamy H. Sarma

Location of the Positive Charges in Cationic Amphiphiles Modulates Their Mechanism of Action against Model Membranes.

Synthetic cationic amphiphiles (CAms) with physicochemical properties similar to antimicrobial peptides are promising molecules in the search for alternative antibiotics to which pathogens cannot easily develop resistance. Here, we investigate two types of CAms based on tartaric acid and containing two hydrophobic chains (of 7 or 11 carbons) and two positive charges, located either at the end of the acyl chains (bola-like, B7 and B11) or at the tartaric acid backbone (gemini-like, G7 and G11). The interaction of the CAms with biomimetic membrane models (anionic and neutral liposomes) was studied with zeta potential and dynamic light scattering measurements, isothermal titration calorimetry, and a fluorescent-based leakage assay. We show that the type of molecule determines the mechanism of action of the CAms. Gemini-like molecules (G7 and G11) interact mainly via electrostatics (exothermic process) and reside in the external vesicle leaflet, altering substantially the vesicle surface potential but not causing significant membrane lysis. On the other hand, the interaction of bola-like CAms (B7 and B11) is endothermic and thus entropy-driven, and these molecules reach both membrane leaflets and cause substantial membrane permeabilization, likely after clustering of anionic lipids. The lytic ability is clearly higher against anionic membranes as compared with neutral membranes. Within each class of molecule, longer alkyl chains (i.e., B11 and G11) exhibit higher affinity and lytic ability. Overall, the molecule B11 exhibits a high potential as antimicrobial agent, since it has a high membrane affinity and causes substantial membrane permeabilization.