Mixed monolayer of DPPC and lysine-based cationic surfactants: an investigation into the antimicrobial activity.

In this paper, we report studies which aim to elucidate the mechanisms involved in the antimicrobial activity of three cationic lysine-based surfactants: LLM, LALM, and C6 (LL)2. To this end, a simple membrane model (i.e.

Interaction of a Rhodococcus sp. trehalose lipid biosurfactant with model proteins: thermodynamic and structural changes.

One major application of surfactants is to prevent aggregation during various processes of protein manipulation. In this work, a bacterial trehalose lipid (TL) with biosurfactant activity, secreted by Rhodococcus sp., has been identified and purified.

Effects of a bacterial trehalose lipid on phosphatidylglycerol membranes.

Bacterial trehalose lipids are biosurfactants with potential application in the biomedical/healthcare industry due to their interesting biological properties. Given the amphiphilic nature of trehalose lipids, the understanding of the molecular mechanism of their biological action requires that the interaction between biosurfactant and membranes is known. In this study we examine the interactions between a trehalose lipid from Rhodococcus sp.

Hemolytic activity of a bacterial trehalose lipid biosurfactant produced by Rhodococcus sp.: evidence for a colloid-osmotic mechanism.

A succinoyl trehalose lipid produced by Rhodococcus sp. behaves as a biological surfactant and also displays various interesting biological activities. Trehalose lipid has been shown to have a great tendency to partition into phospholipid membranes; therefore, the characterization of its interaction with biological membranes is of central importance.

Permeabilization of biological and artificial membranes by a bacterial dirhamnolipid produced by Pseudomonas aeruginosa.

Pseudomonas aeruginosa, when cultured under the appropriate conditions, secretes rhamnolipids to the external medium. These glycolipids constitute one of the most interesting classes of biosurfactants so far. A dirhamnolipid fraction was isolated and purified from the crude biosurfactant, and its action on model and biological membranes was studied.

Mechanism of membrane permeabilization by a bacterial trehalose lipid biosurfactant produced by Rhodococcus sp.

The interactions of a succinoyl bacterial trehalose lipid biosurfactant produced by Rhodococcus sp. with phospholipid vesicles, leading to membrane permeabilization, are studied by means of calorimetric and fluorescence and absorption spectroscopical techniques in search for a molecular model. The critical micelle concentration (CMC) of trehalose lipid is determined, by surface tension measurements, to be 300 muM.

Interactions of a bacterial biosurfactant trehalose lipid with phosphatidylserine membranes.

Trehalose lipids are biosurfactants produced by rhodococci that, in addition to their well known potential industrial and environmental uses, are gaining interest in their use as therapeutic agents. The study of the interaction of biosurfactants with membranes is important in order to understand the molecular mechanism of their biological actions. In this work we look into the interactions of a bacterial trehalose lipid produced by Rhodococcus sp.

Interactions of a Rhodococcus sp. biosurfactant trehalose lipid with phosphatidylethanolamine membranes.

Trehalose lipids are an important group of glycolipid biosurfasctants mainly produced by rhodococci. Beside their known industrial applications, there is an increasing interest in the use of these biosurfactants as therapeutic agents. We have purified a trehalose lipid from Rhodococcus sp.

Thermodynamic and structural changes associated with the interaction of a dirhamnolipid biosurfactant with bovine serum albumin.

The interaction of a dirhamnolipid biosurfactant secreted by Pseudomonas aeruginosa with bovine serum albumin was studied by means of various physical techniques. Binding of the biosurfactant to bovine serum albumin was first characterized by isothermal titration calorimetry, showing that one or two molecules of dirhamnolipid, in the monomer state, bound to one molecule of the protein with high affinity. These results were confirmed by surface tension measurements in the absence and presence of bovine serum albumin.

Domain formation by a Rhodococcus sp. biosurfactant trehalose lipid incorporated into phosphatidylcholine membranes.

The study of the interaction of biosurfactants with biological membranes is of great interest in order to gain insight into the molecular mechanisms of their biological actions. In this work we report on the interaction of a bacterial trehalose lipid produced by Rhodococcus sp. with phosphatidylcholine membranes.

Thermodynamics of the interaction of a dirhamnolipid biosurfactant secreted by Pseudomonas aeruginosa with phospholipid membranes.

Rhamnolipids are bacterial biosurfactants produced by Pseudomonas spp. These compounds have been shown to present several interesting biological activities, restricting the growth of Bacillus subtilis and showing zoosporicidal activity on zoosporic phytopathogens. It has been suggested that the interaction with the membrane could ultimately be responsible for these actions.

Aggregation behaviour of a dirhamnolipid biosurfactant secreted by Pseudomonas aeruginosa in aqueous media.

The process of micelle formation, along with the formation of higher order aggregates, is described for a dirhamnolipid extracellular biosurfactant secreted by Pseudomonas aeruginosa. As determined by surface tension measurements, at pH 7.4 the CMC of dirhamnolipid is 0.

Effects of dirhamnolipid on the structural properties of phosphatidylcholine membranes.

Rhamnolipids are biosurfactants produced by Pseudomonas aeruginosa which are well known for their potential industrial and environmental uses. Rhamnolipids have gained considerable interest in recent years due to their potential use in cosmetics and pharmaceutics. They also show broad biological activities and have potential applications as therapeutic agents.

Modulation of the physical properties of dielaidoylphosphatidylethanolamine membranes by a dirhamnolipid biosurfactant produced by Pseudomonas aeruginosa.

Rhamnolipids are bacterial biosurfactants produced by Pseudomonas spp. These compounds have been shown to present several interesting biological activities, restricting the growth of Bacillus subtilis and showing zoosporicidal activity on zoosporic phytopathogens. It has been suggested that the interaction with the membrane could be the ultimate responsible for these actions.

Bacterial community dynamics and polycyclic aromatic hydrocarbon degradation during bioremediation of heavily creosote-contaminated soil.

Bacterial community dynamics and biodegradation processes were examined in a highly creosote-contaminated soil undergoing a range of laboratory-based bioremediation treatments. The dynamics of the eubacterial community, the number of heterotrophs and polycyclic aromatic hydrocarbon (PAH) degraders, and the total petroleum hydrocarbon (TPH) and PAH concentrations were monitored during the bioremediation process. TPH and PAHs were significantly degraded in all treatments (72 to 79% and 83 to 87%, respectively), and the biodegradation values were higher when nutrients were not added, especially for benzo(a)anthracene and chrysene.