The influence of newly synthesised fenporpimorph derivatives on some pathogen yeasts.

The effect of minimum inhibitory concentrations (MICs) of six novel fenpropimorph derivatives on lipid and sterol composition of Candida albicans, Cryptococcus neoformans, Malassezia pachydermatis and Malassezia furfur was investigated. The MICs for the most effective derivatives were found in the range from 3.7 to 56.7 microM and were 2-3 times lower compared to the commercial fungicide bifonazol. The more efficient fenpropimorph derivatives were the piperidine derivative for C. albicans and the allylamine derivative for Cr. neoformans, M. pachydermatis and M. furfur. The inhibitor in the growth medium reduced the unsaturation index of the total lipid content in M. furfur and C. albicans.

Influencing the immune parameters in germ-free piglets by administration of seal oil with increased content of omega-3 PUFA.

Oral administration of oil with an increased content of omega-3 polyunsaturated fatty acids to germ-free piglets resulted in a significant increase in the total values of CD4, CD8 lymphocytes, B lymphocytes, and monocytes, in peripheral blood in comparison with the controls. The metabolic activities of phagocytes as well as the polyclonal activation of lymphocytes were not significantly influenced. The level of growth factor was significantly higher, as determined on the basis of somatomedin in the blood serum. Biochemical indices showed a significant increase in the level of eicosapentaenoic and docosahexaenoic acids in blood serum and the decrease in the level of arachidonic acid at the same time.

Influence of methylfenpropidine on growth, sterol content and fatty acid composition of Candida albicans.

The effect of methylfenpropidine on growth, lipid contents, sterol and fatty acid composition was investigated in 5 strains of Candida albicans. The sensitivity of the strains decreased in the order: wild strains > erg+ ade nysR > ade nysR erg (defective delta (8-7)-isomerase) > ade nysR erg (defective delta 5-desaturase). The presence of the inhibitor influenced fecosterol isomerization, episterol dehydrogenation, zymosterol transmethylation, ignosterol reduction and squalene epoxidation. Methylfenpropidine also induced changes in fatty acid composition, causing a reduction of the palmitic and oleic acid content with a concomitant elevation of stearic, linoleic and linolenic acid levels. The lipid unsaturation index slightly increased. Morphological changes of wild strains were observed after the fungicide treatment.

Effect of oil containing n-3 polyunsaturated fatty acids (PUFA) on the immune response and growth factors in piglets.

Oral administration of n-3 polyunsaturated fatty acids (PUFA) to piglets slightly enhances the immune response. As compared to the control, in the experimental piglets the absolute values of monocytes in the peripheral blood were significantly increased (P < 0.05), while the metabolic activity of phagocytes and the number of lymphocytes within the individual subpopulations were slightly higher. The level of growth factors, determined on the basis of somatomedin in the blood serum, was significantly higher in the experimental group (P < 0.05). n-3 PUFA interfere with the synthesis of prostaglandins and influence the metabolism of fatty acids. This finding may contribute to the therapy of inflammatory processes influencing immune and growth factors in piglets.

The content of prostaglandins and their precursors in Mortierella and Cunninghamella species.

Five strains of filamentous fungi belonging to the genera Mortierella and Cunninghamella were examined for the content of dihomo-gamma-linolenic, arachidonic, eicosapentaenoic acids and prostaglandins (type E2 and F2 alpha). Prostaglandins were detected using an ELISA method in mycelia of all tested strains (range 50-4800 ng g-1 of PGE2 and 6-30 ng g-1 of PGF2 alpha). Several micro-organisms also produced prostaglandins in the culture medium (2.2-137.6 micrograms 1-1 for PGE2 and 0.4-7.8 micrograms 1-1 for PGF2 alpha).

Influence of new fenpropimorph fungicides on the growth and sterol composition in Saccharomyces cerevisiae: relationship between structure and activity.

The toxicity of fenpropimorph and seven newly synthesized analogues against Saccharomyces cerevisiae has been determined in liquid media. The inhibitory effect of the most efficient derivative is 120 times more than that of standard fenpropimorph. The non-linear relationship between hydrophobicity and toxicity indicates that the binding of the compounds to the receptors does not differ and so the differences in toxicity reflect changes in the rate of metabolism. The presence of inhibitors in the fermentation medium resulted in a reduction in harvested biomass and lipid yield, and changes in sterol composition -- the amount of ergosterol decreased whereas the amounts of lanosterol, dihydroergosterol and squalene increased. The toxicity of the compounds was most influenced by their lipophilicity. Use of this information could lead to development of more potent ergosterol inhibitors.

Effect of some environmental factors on the content and composition of microbial membrane lipids.

Lipids are known as a part of an effective adaptation mechanism reflecting the changes in the extracellular environment. The fluidity of biological membranes is influenced by the lipid structure and the portion of saturated, unsaturated, branched, or cyclic fatty acids in individual phospholipids. For all living organisms undergoing environmental adaptation, the fluidity can be changed only to a relatively small extent. This range is genetically determined and it is specific for every microorganism. This article presents recent knowledge about the influence of some environmental parameters (temperature, osmotic pressure, pH, the presence of salt or ethanol in medium) on a microbial membrane with the emphasis on regulation aspect in fatty acid biosynthesis. The main tools for regulation of membrane fluidity, for example, fatty acid desaturation or incorporation of branched and cyclic fatty acids into phospholipids, are discussed in more detail.

Influence of ethanol on the lipid content and fatty acid composition of Saccharomyces cerevisiae.

The content of total lipid as well as of ergosterol, squalene, and major fatty acids were compared in the cells of a distillery strain of Saccharomyces cerevisiae incubated for 3, 48 and 120 h in the presence of 5, 10 and 15% ethanol. Ethanol induced lipid accumulation with preferential ergosterol biosynthesis. The relative contents of palmitic and stearic acid decreased whereas the amount of palmitoleic and oleic acid increased. The total content of all fatty acids rose as a consequence of the ethanol treatment.

Effect of salt stress on fatty acid alterations in some strains of Dipodascopsis and Dipodascus spp.

The effect of salt stress (8% w/v NaCl) on fatty acid composition of eight strains of Dipodascus and Dipodascopsis spp. varied from being of slight influence only (Dipodascopsis uninucleata), to decreasing the content of 18:2 (D. reesii, D. tetrasperma and D. australiensis) and to decreasing both 18:1 and 18:2 (D. tothii and D. aggregatus) with a concomitant rise of 14:1 and 16:1. With the exception of D. aggregatus, NaCl inhibited lipid accumulation in all strains. Only trace amounts of fatty acids over C18 in chain length were found.

Fatty acid alterations in Saccharomyces cerevisiae exposed to ethanol stress.

The influence of ethanol concentration on fatty acid alterations in total phospholipids (PL), phosphatidylcholine (PCH), phosphatidylethanolamine (PE), phosphatidylinositol (PI), sterol esters (ES) and triacylglycerols (TAG) of Saccharomyces cerevisiae was studied. Ethanol induced the elevation of palmitic and oleic acid level in major membrane phospholipids (PCH and PE) and also the palmitoleic acid content in ES and TAG.

Oligounsaturated fatty acid production by selected strains of micromycetes.

Fifteen strains of filamentous fungi from the Culture Collection of Fungi (Charles University, Prague) were tested for their lipid production, fatty acid composition with emphasis on accumulation of oligounsaturated fatty acids. All cultures contained palmitic (16:0), palmitoleic (16:1), stearic (18:0), oleic (18:1), linoleic (18:2) and gamma-linolenic (18:3) acid (GLA). The mycelium of Cunninghamella elegans, Rhizopus arrhizus, Mortierella parvispora, M. elongata and M. alpina contained arachidonic acid (ARA) in the range of 2.3-33.5% of the total fatty acids. The strains used in our experiment were capable to accumulate a relatively high amount of intracellular lipid (9.6-20.1% in dry biomass). The highest content of GLA (22.3 mg/g) was found in Mucor circinelloides. The strain of M. alpina containing 47.1 mg/g of ARA could be considered as the best producer of ARA.

Malassezia pachydermatis: properties and storage.

Five strains of Malassezia pachydermatis isolated from small animals in Bratislava were subcultured, maintained under sterile paraffin oil and preserved in liquid nitrogen. Morphological and physiological characteristics as well as the analysis of long chain fatty acids of the cell mass were determined. The results showed that the maintenance in liquid nitrogen is the most satisfactory method of preservation of pure cultures of Malassezia pachydermatis.

Lipids in yeast cell wall glucans.

Lipids isolated from glucans of Saccharomyces cerevisiae were analysed by thin-layer chromatography, infrared spectroscopy and gas-liquid chromatography. Localization of glucan lipid in the polysaccharide net was observed by light and electron microscopy. Despite using Manner's method for glucan preparation, the residue of acidic lipid occupied a central position in the treated cells. Analysis showed the presence of free fatty acids in which a relatively high content of vaccenic acid was detected.

Selection of Rhizopus strains for L(+)-lactic acid and gamma-linolenic acid production.

The production of L(+)-lactic acid and formation of gamma-linolenic acid by 50 Rhizopus strains growing on saccharidic substrates were investigated. Formation of acids was observed on solid cultivation media but mainly during submerged fermentation. Strains with the highest selectivity of both L(+)-lactic acid production and gamma-linolenic acid formation were tested in a laboratory fermenter. The best producer was treated by UV irradiation to increase the fatty acid content in the biomass, especially that of gamma-linolenic acid. The conversion of 10% saccharidic substrate by this newly prepared strain Rhizopus arrhizus CCM 8109 results in more than 95% of theoretical yield of L(+)-lactic acid and permits a volume productivity of 0.4 g gamma-linolenic acid per liter.