Effects of rhamnolipid-biosurfactant on cell surface of Pseudomonas aeruginosa.

The effect of rhamnolipid-biosurfactant produced by Pseudomonas sp. PS-17 on cell surface structures of Pseudomonas aeruginosa NBIMCC 1390 was studied. The results demonstrated that the rhamnolipid at concentrations below and above CMC provoked a multi-component response of the bacterial cells without affecting their growth and viability. Above CMC, the rhamnolipid caused reduction of total cellular LPS content of 22%, which can be associated with an increase in cell hydrophobicity to 31% adherence. The rhamnolipid-biosurfactant at concentration below CMC did not affect the LPS component of the bacterial outer membrane but caused changes in OMP composition of P. aeruginosa. Examination of the OMP profiles revealed that the amount of major proteins (Opr F, Opr D, Opr J and Opr M) markedly decreased. To our knowledge this is the first report on the rhamnolipid-biosurfactant interactions with bacterial cells showing changes in outer membrane proteins of P. aeruginosa. In both concentrations, the biosurfactant caused changes in cell surface morphology. The results indicate that the rhamnolipid-biosurfactant from Pseudomonas sp. PS-17 has a potential application in the relatively new field of biomedicine.

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. Cell permeabilization with biosurfactant PS was shown to be more effective with B. subtilis resting cells than with Pseudomonas aeruginosa. Scanning-electron microscopy observations showed that the biosurfactant PS did not exert a disruptive action on resting cells such that it was detrimental to the effect on growing cells of B. subtilis. Low critical micelle concentrations, tender action on nongrowing cells, and neutral effects on the growth of microbial strains at low surfactant concentrations make biosurfactant PS a potential candidate for application in different industrial fields, in environmental bioremediation, and in biomedicine.

Purification and partial characterization of acid phosphatase from Candida lipolytica.

Non-specific acid phosphatase from Candida lipolytica cells was purified 111-fold by chromatography on DEAE-cellulose and gel filtration on Sephadex G-100 and Sepharose 4B. The enzyme is a glycoprotein containing 67% neutral sugars. The molecular mass of the highly purified acid phosphatase was found to be approximately 95 kDa by both SDS-PAGE and gel filtration. The pH and temperature optima were 5.8 and 55 degrees C, respectively. The enzyme was stable at pH values between 3.5 and 5.5 and at temperatures up to 60 degrees C. The purified phosphatase had a Km value of 3.64 mM for p-nitrophenyl phosphate and showed broad substrate specificity.

[Effects of physical activity and mid-alpine climatotherapy on serum lipids on adult diabetics and in obesity]. / Efekti na fizicheskata aktivnost i srednoplaninskoto klimatolechenie vurkhu serumnite lipidi u bolni diabet na zrialata vuzrast i zatlustiavane.

Observations and investigations were carried out on 50 patients with diabetes of mature years and light obesity of nutritional-metabolic type in a moderately high mountain (1870 m above sea level). After 20-day treatment, including daily, lasting physical loadings, cool sun-air exposures and moderately reducing diet of 1600-1800 kcal, a clinically significant reduction of a wide range 6,699-7,537 MJ = of lipid indices was established, namely--total fats, total cholesterol, beta lipoproteins, triglycerides, esterified fatty acids and lipoproteins with low density (LDL-cholesterol), an average with 9.3 to 19.5 per cent. A more pronounced reduction of lipid indices was established with higher initial values and moderate weight reduction with 3.5 kg for a 20-day treatment course. The physical loadings and cool sun-air exposure stimulated the lipolysis, the elevated levels of free fatty acids being chiefly used for energy supply of organism. The enhanced lipolysis was, very, likely, of essential significance for the favourable effect of hyperlipidemia.

[Changes in the indices of fat metabolism in obesity during physical activity, on a reducing diet and during meterological influences]. / Promeni v pokazatelite na mastniia metaolizum u bolni sus zatlustiavane pri fizicheska aktivnost, redutsirashta dieta i meterologichni vuzdeistviia.

Clinical experimental investigations were carried out of 96 patients with light, nutritional-metabolism forms of obesity under the conditions of a moderately high mountain (1870 m above the sea level). After a treatment course of 20--25 days including: reducing diet, physical loading and cool sun-air exposure, a significant decrease of a wide spectrum of lipid indices was found, namely: total lipids, triglycerides, total cholesterol, phospholipids and beta-lipoproteins. A significant correlation was established between cholesterol decrease and beta-lipoproteins with body weight reduction over 3 kg and the high initial values of the indices. With a single physical loading in the patients with obesity -- the elevation of NEFA does not considerably differ from that of the control group with neurasthenia. The glucose loading is admitted not to indice manifested lipogenesis with the physical loading and cool sun-air exposure.