Towards Rational Biosurfactant Design-Predicting Solubilization in Rhamnolipid Solutions.

The efficiency of micellar solubilization is dictated inter alia by the properties of the solubilizate, the type of surfactant, and environmental conditions of the process. We, therefore, hypothesized that using the descriptors of the aforementioned features we can predict the solubilization efficiency, expressed as molar solubilization ratio (MSR). In other words, we aimed at creating a model to find the optimal surfactant and environmental conditions in order to solubilize the substance of interest (oil, drug, etc.

Rhamnolipid CMC prediction.

Relationships between the purity, pH, hydrophobicity (logK) of the carbon substrate, and the critical micelle concentration (CMC) of rhamnolipid type biosurfactants (RL) were investigated using a quantitative structure-property relationship (QSPR) approach and are presented here for the first time. Measured and literature CMC values of 97 RLs, representing biosurfactants at different stages of purification, were considered. An arbitrary scale for RLs purity was proposed and used in the modelling.

[Effect of a new low-cholesterol meat and vegetal product on correction of simulated lipid metabolism disorders in rats].

The paper presents the biomedical evaluation of meat and cereal spread from low-cholesterol raw material with vegetable ingredients, recommended as a functional food. The experimental model with myocardial infarction like changes in hearts of the animals, accompanied by vascular changes similar to atherosclerotic changes in humans, as well as the modeling of the metabolic imbalance of lipids have been carried out by intramuscular injection of epinephrine and unbalanced feeding the animals with food rich in cholesterol, with a high content of carbohydrates and fats. Wistar rats were divided into 4 groups of 12 animals each.

[Ranking of radionuclides and pathways according to their contribution to the dose burden to the population resulting from NPP releases].

Approaches are described towards estimating the consequences of radioactive contamination of ecosystems by nuclear fuel cycle enterprises with the rationale for the optimal specification level for nuclear power plants (NPP) operating in the normal mode. Calculations are made based on the initial data of the IAEA project, INPRO ENV, dealing with the ranking of radionuclides escaping to the environment from the operating NPPs. Influence of various factors on rankings of radionuclides and pathways of public exposure is demon- strated.

The importance of rhamnolipid-biosurfactant-induced changes in bacterial membrane lipids of Bacillus subtilis for the antimicrobial activity of thiosulfonates.

The antimicrobial properties of methyl (MTS) and ethyl (ETS) esters of thiosulfonic acid alone and in combination with rhamnolipid-biosurfactant (RL) have been characterized for their ability to disrupt the normal physiological functions of living pathogens. Bactericidal and fungicidal activities of MTS and ETS and their combination with rhamnolipid were demonstrated on strains of Pseudomonas aeruginosa, Bacillus subtilis, Alcaligenes faecalis, and Rhizopus ngtricans. It was found that the combination of rhamnolipid and thiosulfonic esters has a synergistic effect leading to decreasing of bactericidal and fungicidal concentrations of MTS and ETS.

Radionuclide transfer to freshwater biota species: review of Russian language studies.

Around 130 publications reporting studies on radionuclide transfer to freshwater biota species conducted in the former USSR were reviewed to provide the concentration ratio values. None of these studies were available up to now in the English language reviews or publications. The values derived have been compared with the CR values used for freshwater systems in the International reviews.

Radionuclide transfer to marine biota species: review of Russian language studies.

An extensive programme of experiments on transfer of radionuclides to aquatic species was conducted in the former USSR starting from the early 1950s. Only a few of these studies were made available in the English language literature or taken into account in international reviews of radionuclide behaviour in marine ecosystems. Therefore, an overview of original information on radionuclide transfer to marine biota species available from Russian language literature sources is presented here.

[The dose estimation of woody plants in the long-term after the Chernobyl NPP accident].

Dosimetric models have been developed to estimate the exposure doses of woody plants growing in the area contaminated by long-lived radionuclides. The models are parameterized based on the data obtained from the experimental plots in the south-west districts of the Bryansk region affected by radioactive fallout of the Chernobyl NPP accident. Doses are estimated to generative organs of pine trees from these plots.

Anti-herpesvirus activities of Pseudomonas sp. S-17 rhamnolipid and its complex with alginate.

The rhamnolipid biosurfactant PS-17 and its complex with the polysaccharide alginate, both produced by the Pseudomonas sp. S-17 strain, were studied for their antiviral activity against herpes simplex virus (HSV) types 1 and 2. They significantly inhibited the herpesvirus cytopathic effect (CPE) in the Madin-Darby bovine kidney (MDBK) cell line.

Rhamnolipid-biosurfactant permeabilizing effects on gram-positive and gram-negative bacterial strains.

The potential of biosurfactant PS to permeabilize bacterial cells of Pseudomonas aeruginosa, Escherichia coli, and Bacillus subtilis on growing (in vivo) and resting (in vitro) cells was studied. Biosurfactant was shown to have a neutral or detrimental effect on the growth of Gram-positive strains, and this was dependent on the surfactant concentration. The growth of Gram-negative strains was not influenced by the presence of biosurfactant in the media.

[The prospects of using bacteria of the genus Rhodococcus and microbial surfactants for the degradation of oil pollutants].

The possibility of accelerating oil degradation by an enrichment culture of oil-oxidizing microorganisms in the presence of bacteria of the genus Rhodococcus and microbial surfactants was studied. It was shown that the degree of consumption of crude oil (2% v/v) after 192 h of enrichment culture growth reached 84%. Inoculation of the active hydrocarbon-oxidizing strain Rhodococcus erythropolis EK-1 and exogenous surfactants produced by Pseudomonas sp.

Semax, an analogue of adrenocorticotropin (4-10), binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain.

The heptapeptide Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is an analogue of the N-terminal fragment (4-10) of adrenocorticotropic hormone which, after intranasal application, has profound effects on learning and memory formation in rodents and humans, and also exerts marked neuroprotective effects. A clue to the molecular mechanism underlying this neurotropic action was recently given by the observation that Semax stimulates the synthesis of brain-derived neurotrophic factor (BDNF), a potent modulator of synaptic plasticity, in astrocytes cultured from rat basal forebrain. In the present study, we investigated whether Semax affects BDNF levels in rat basal forebrain upon intranasal application of the peptide.

[Production of surfactants by Rhodococcus erythropolis strain EK-1, grown on hydrophilic and hydrophobic substrates].

The ability of Rhodococcus erythropolis strain EK-1 to produce surfactants when grown on hydrophilic (ethanol and glucose) and hydrophobic (liquid paraffins and hexadecane) substrates was studied. The strain was found to produce surfactants with emulsifying and surface-active properties. The production of surfactants depended on the composition of the nutritive medium, nature and concentration of the sources of carbon and nitrogen, and duration of cultivation.

[Experimental basis for the use of new dosage forms of doxorubicin for correction of its hepatotoxic, prooxidant and immunosuppressory effects].

The study was aimed at design of new dosage forms of doxorubicin (films, erythrocyte vehicles) for correction of its hepatotoxic, prooxidant and immunosuppressory effects. The experiments were performed on Wistar rats with the use of doxorubicin of Lens-Pharm (Moscow) and auxiliary substances meeting the requirements of the standards. Technology for preparation of doxorubicin-entrapped films was developed and the optimal polymer for the vehicle was recommended, i.

Biosurfactant-rhamnolipid effects on yeast cells.

Aim: The aim of this work was to study the effect of the novel surfactant PS from Pseudomonas sp. S-17 on Saccharomyces cerevisiae 83-20 yeast cells and to compare it with the effect of the well known surfactant Triton X-100.

Methods And Results: The effect of surfactants was investigated on the cells during growth, and on the separated cells.

[The surface-active compounds of a Pseudomonas sp. S-27 culture].

Pseudomonas species S-27 was grown on various substrates. It was established that the Pseudomonas species S-27 strain can produce biosurfactants of ramnolipid nature decreasing the surface and interfacial tension to 29.2 and 0.

[A method for determining the content of anionogenic surface-active peptidolipids of bacterial origin].

The simple and selective method of anionic biosurfactant concentration determination in bacterial cultural broth is offered. The method is based on the ability of the anionic surfactants to form some coloured complex with the cationic indicator methylene blue registered by spectrophotometer. The suggested method is recommended for the study of biosynthesis of microbial surfactants.

[The characteristics of the biosynthesis of surface-active lipids by a Bacillus sp. culture].

It is established that the Bacillus sp. C-14 strain is able to produce the biosurfactant of lipopeptide nature which decreases the surface and interfacial tension to 29.5 and 2.

[Cimetidine pharmacokinetics].

The pharmacokinetics of cimetidine was studied in 9 patients at a single intravenous (200 mg) and oral (400 mg) administration. The pharmacokinetic parameters at intravenous administration were calculated according to a two-compartment model. The time-concentration curve after oral drug administration had two maxima between 45 min and 2 hrs with approximately equal concentrations of cimetidine.