Kamen Stefanov

Fatty acid composition of some algae from the black sea

Abstract The fatty acid compositions were determined of two marine algae of the Rhodophyceae, one of the Phaeophyceae and four of the Chlorophyceae, from the Black Sea in Bulgaria. The results may be of value for taxonomic purposes.

Silver ion high-performance liquid chromatography and gas chromatography—mass spectrometry in the analysis of complex fatty acid mixtures: application to marine invertebrates

Abstract High-performance liquid chromatography on a stable silver ion column permitted the isolation of clean fractions differing in degree of unsaturation, with zero to six double bonds, of the methyl ester derivatives of fatty acids from complex lipid samples. By a combination of gas chromatographic analysis of the methyl esters on capillary columns coated with polar phases, and gas chromatography-mass spectrometry of the picolinyl ester derivatives, separated on non-polar phases, most components can be identified. In order to demonstrate the methodology, fatty acids from the Black Sea invertebrates Mytilus galloprovincialis and Rapana thomasiana were separated into 41 and 46 defined components, respectively (58 different fatty acids in total), and full quantitative analyses were achieved of most constituents present at levels of about 0.1% of the total and above. The fatty acids found included mono- and multi-methyl branched isomers, mono- and polyunsaturated fatty acids of the (n-1), (n-3), (n-4), (n-5), (n-6), (n-7), (n-8), (n-9), (n-11) and (n-13) families, and dienoic acids with several methylene groups between the double bonds, ranging in chain length from C13 to C22.

Separation of picolinyl ester derivatives of fatty acids by high-performance liquid chromatography for identification by mass spectrometry

Abstract The picolinyl ester derivatives of the fatty acids of cod liver oil and of pig testis lipids were separated by high-performance liquid chromatography (HPLC) in the reversed-phase mode on a column containing an octyl-bonded phase. To obtain satisfactory resolution, it was necessary to use a mobile phase containing pyridine, which precluded the use of UV spectrophotometric detection. It was, however, possible to use the mass detector with a stream-splitter. Each of the fractions obtained was then analysed by gas—liquid chromatography—mass spectrometry, with separation on a column of fused silica coated witha a methylsilicone phase. From the mass spectra, it was possible to identify 39 and 32 different fatty acid components from cod liver oil and pig lipids respectively. A high proportion of these were not resolved when the samples were analysed without pre-fractionated by HPLC.

The fatty acids of the spongeDysidea fragilis from the black sea

The fatty acid composition of the sponge,Dysidea fragilis, from the Black Sea has been determined by analytical gas chromatography, silver ion high-performance liquid chromatography and gas chromatography/mass spectrometry. More than a hundred different fatty acids were identified, of which many were similar to those in sponges from tropical seas. On the other hand, some of the fatty acids identified have not been found previously in sponges or other marine sources and perhaps are new to science. These include 13-methyl-tetradec-4-enoic and 14-methyl-hexadec-6-enoic acids, together with demospongic acids,i.e. 5,9,17-tetracosatrienoic, 5,9,17-pentacosatrienoic and 5,9,19-pentacosatrienoic acids. From the elution behavior on silver nitrate chromatography, all the double bonds were of thecis-configuration.

Effect of salinity on lipid composition of Cladophora vagabunda

The main lipid classes and their fatty acid composition were investigated in Cladophora vagabunda inhabiting waters with different salinities or subjected to salt-stress. Most of the observed changes probably have adaptive value. Differences between adaptation and stress, and also the effects of the degree of the stress are discussed.

Lipid and sterol changes in leaves of Haberlea rhodopensi and Ramonda serbica at transition from biosis into anabiosis and vice versa caused by water stress

Abstract The lipid and sterol composition of leaves of Haberlea rhodopensis and Ramonda serbica and their changes at different water deficits and restoration from anabiosis in light and dark were investigated. Lipid and sterol composition changes more drastically at 50% water deficit, while at 87% water deficit (air-dried plant) it is similar to that of fresh plants. This is an indication that there is almost full adaptation of the investigated plants in the stage of anabiosis. The restoration in light leads to lipid and sterol composition similar to that of the fresh plants, while restoration in dark leads to a composition similar to that of half-dried plants.

Effect of Lead Ions on the Phospholipid Composition in Leaves of Zea mays and Phaseolus vulgaris

Summary The composition of the main phospholipids: phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol and phosphatidyl glycerol in leaves of Z. mays and P. vulgaris , as well as their changes after treatment of the plants with lead and sodium acetate were investigated. The relative concentrations of individual PL were affected significantly by lead and acetate ions. Lead treatment caused an increase of phospholipid concentrations. The relative concentrations of phosphatidyl glycerol decreased and these of phosphatidyl choline increased. Sodium acetate treatment probably leads to some type of salt stress, resulting in an increase of phosphatidyl glycerol concentrations and decrease of phosphatidyl ethanolamine concentrations. The amount of saturated fatty acids decreased and these of linolenic acid increased in all investigated samples.

Development in primary cell culture of demosponges.

We have established primary cell culture of the marine demosponge Dysidea avara and Suberites domuncula. Microbial contamination was controlled by the use of a pool of antibiotics confirming the goodness of this procedure. Effect of pH, temperature and light was studied to establish the better growth conditions. The comparison of lipid composition of sponge and cells suggested a series of experiments to optimise the medium. A glucose dose-dependent experiment showed that the ideal glucose concentration is 1 g l(-1). Supplementing the medium with unsaturated fatty acid and retinol, no promotion of growth was observed, but the compounds were totally metabolised by cells. Increments from 70 to 160% in the number of cells were observed, supplementing the medium with different concentration of cholesterol. These results suggest that the analysis of the chemical composition of sponge and cells give indication on the composition of the nutrient media.

Antibacterial, antiviral, and cytotoxic activities of some red and brown seaweeds from the Black Sea.

Abstract Chloroform extracts, n- butanol extracts, water extracts,and volatile compounds from seven species belongingtosix Black Sea genera of brown algae and 10 speciesbelonging to seven Black Sea genera of red algae wereassessed for antibacterial, antiviral, and cytotoxic prop-erties. Most of the extracts showed pronounced effectsagainst the Gram (q) bacterium Staphylococcus aureus .Activity towards the Gram (-) bacterium Escherichia coli was found in only few cases. A significant reduction inreplication of influenza and Herpes simplex viruses in cellcultures was observed. Cytotoxic effect was establishedin a significant proportion of the algae investigated. Thebiological activities may be attributed to the presence ofvolatile compounds, some phenols, free fatty acids andtheir oxidized derivatives, eucalyptol, the methyl ester ofphenyl acetic acid, and 1,2-dihydroxy ethane sulfonate. Keywords: biological activities; extracts; red and brownBlack Sea algae. Introduction Marine algae have been evaluated as an attractivesourceof potential drug compounds in several biochemical andpharmacological investigations (Kerr and Kerr 1999,Luescher-Mattli 2003, Simmons et al. 2005, Lahaye andRobic 2007). Being in permanent contact with pollutants(and in order to survive in such unfriendly environments),different marine organisms, such as fungi, viruses, bac-teria, etc., synthesize or accumulate defensive com-pounds. Diverse algal extracts have been investigatedfortheir antimicrobial, cytotoxic, antitumor, antiviral, andanti-inflammatory properties (Konig and Wright 1996,Mandal et al. 2007). Our preliminary investigationsshowed that some widespread Black Sea algae possessantimicrobial, antiviral, antifungal and cytotoxic activities(Stefanov et al. 1998, Kujumdjiev et al. 1999, Serkedjieva2000, Kamenarska et al. 2002). Evidently, most of thebiologically active compounds found in marine algaehave defensive functions. A proportion of these com-pounds are secreted into surrounding seawater.In the present study, we continued the investigation ofantibacterial, cytotoxic, and antiviral activities of themostwidely distributed macroalgae in the Bulgarian part of theBlack Sea, which has not been studied until now. More-over, the results obtained were compared with the chem-ical compositions of the corresponding extracts.

Comparative investigation of phospholipids and fatty acids of freshwater molluscs from the Volga River basin

1. Four Gastropoda species and two Bivalvia species from the Volga river basin were examined. 2. Distribution of phospholipids in the molluscs was studied by qualitative and quantitative micro thin-layer chromatography. 3. Major phospholipid classes, phosphatidylethanolamine and phosphatidylcholine, were found to contain plasmalogens. 4. One mollusc species notably contained 67 fatty acids including 25 saturated (both iso and anteiso), 24 monoenoic, five dienoic, four trienoic and eight polyenoic compounds identified by capillary gas chromatography; fatty acid contents in the other studied species were considerably lower. 5. Relatively high concentrations of nonmethylene-interrupted fatty acids were detected in certain examined species.