Carotenoids produced by yeast biomass protect mechanisms regulating endothelial barrier function from lipopolysaccharide-induced damage in the rat heart.

Expression of occludin and junctional adhesion molecule A (JAM-A), transmembrane proteins of tight junctions (TJs), was analysed to characterize endothelial paracellular permeability in the heart of rats subjected to a bolus of bacterial lipopolysaccharide (LPS) at a dose of 1 mg/kg. Potential protective effects of natural carotenoids (10 mg/kg/day) produced by yeast biomass Rhodosporidium kratochvilovae on expression of occludin and JAM-A also examined in LPS-injected rats (n = 6 per group). LPS decreased expression of occludin by 40% (P < 0.01), JAM-A by 36% (P < 0.001) and increased plasma levels of malondialdehyde (MDA) and lysosomal N-acetyl-b-D-glucosaminidase (NAGA) compared to controls. Ten-day diet rich in yeast biomass containing carotenoids (torularhodin, torulene, ß-carotene) attenuated LPS-induced changes in expression of TJ proteins as observed by increased expression of occludin by 30% (P < 0.05) and JAM-A by 61% (P < 0.001) to the control values. Carotenoids also reduced oxidative stress and cellular injury indicated by decreased levels of MDA and NAGA. The results show that diet rich in yeast biomass containing natural carotenoids could protect mechanisms regulating paracellular endothelial barrier function from LPS-induced damage in the heart.

Effect of yeast biomass with high content of carotenoids on erythrocyte deformability, NO production and Na,K-ATPase activity in healthy and LPS treated rats.

Measurements of red blood cell (RBC) deformability together with estimation of NO-synthase activity and Na,K-ATPase activity were used for characterization of RBC functionality in rats subjected to single dose of Escherichia coli lipopolysaccharides (LPS) at a dose of 1 mg/kg. We hypothesized that LPS might initiate a malfunction of RBC. We also investigated the potential effect of carotenoids (10 mg/kg/day) produced in red yeast biomass of Rhodotorula glutinis on RBC in LPS-challenged rats. LPS significantly reduced the deformability of RBC (by 14%) together with decrease of NO-synthase activity by 20%. Daily supplementation of carotenoids for 10 days attenuated the LPS-induced injury, as observed by 22% increase of RBC deformability and 23% increase of NO-synthase activity. The activity of Na,K-ATPase was also improved probably due to increased number of active enzyme molecules as indicated by 66% enhancement of Vmax value, hence maintaining the activity of erythrocyte Na,K-ATPase to the level even higher as compared with healthy control animals. It may be concluded that administration of yeast biomass with high content of carotenoids resulted in advanced function of erythrocytes as concerns their ability to squeeze through narrow capillaries of the circulation, better intrinsic production of NO and improvement of intracellular homeostasis of sodium.

Influence of viscous Rhodella grisea (Rhodophyceae) proteoglycan on chemically induced cough reflex.

An algal extracellular biopolymer (over 8.5 × 10(5)Da) composed of carbohydrates (52%) and protein (∼13%) has been isolated from a red alga Rhodella grisea growing in natural conditions by concentration of water medium, alcohol precipitation, dialysis and freeze-drying. This mucilagineous biopolymer contained xylose and its 3-O- and 4-O-methyl derivatives (∼63%), galactose (∼12%), glucuronic acid (11-12%), glucose (∼5%), rhamnose (∼4%), fucose (∼3-4%) and low content of others accompaning sugars. When tested on the citric acid-induced cough and reactivity of airways smooth muscle in vivo in the test system guinea pigs, this biopolymer assigned a significant cough suppressing effect. The reactivity of airways smooth muscle was not affected indicating that expectoration effect was not suppressed by biopolymer application, which is important from the pharmacological point of view.

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.

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.

Yeast exoglycoproteins produced under NaCl-stress conditions as efficient cryoprotective agents.

Six extracellular yeast glycoproteins were prepared from three yeast species in osmotic equilibrium and unequilibrium environments and used as non-penetrating cryoadditives. The glycoprotein secreted by the strain Dipodascus australiensis into the growth medium containing NaCl (8% w/v) was found to be the most effective cryoadditive. It was possible to use this glycoprotein alone (without penetrating agent DMSO) for the cryoprotection of the yeasts studied.

Effect of supplementation of University of Wisconsin solution with glycoproteins from psychrophilic strains of yeast on hypothermic liver storage of rats.

Extracellular yeast glycoproteins (YG) produced by Rhodosporidium toruloides have been shown to increase the survival rate of different yeast species after storage in liquid nitrogen. The purpose of this study was to investigate the effect of YG on cold-stored rat livers. Water-soluble YG produced either by Phaffia rhodozyma (G3) or by Leucosporidium antarcticum (G4) were added to a modified University of Wisconsin solution (mUW) and used for cold storage (1 degree C) of isolated livers. The functional status of each liver was then assessed under conditions of 90-min normothermic reperfusion. The 46-h cold storage in mUW without G3 and G4 resulted in serious preservation-reperfusion injury of the liver. The addition of G3 to mUW for 46-h preservation of the liver resulted in significantly higher bile flow (4.32 +/- 0.35 vs 2.35 +/- 0.49 microliters/min/10 g at 75-90 min), higher portal blood flow (10.99 +/- 0.2 vs 4.78 +/- 1.07 ml/min/g at 90 min), lower liver weight after reperfusion (102.4 +/- 1.5 vs 116.7 +/- 6.6% of weight before preservation), and lower total tissue water after reperfusion (2.49 +/- 0.05 vs 2.92 +/- 0.13 g water/g dry weight). However, the activity of ALT, AST, and LDH in perfusate was not changed. The beneficial effect of G4 was less pronounced. The 24-h storage in mUW resulted in a significant increase of AST and LDH activity in perfusate; the addition of G3 to mUW for 24-h preservation did not affect these parameters. In conclusion, the addition of 0.05% G3 or G4 to mUW was only partially beneficial in improving rat liver preservation.

Cryoprotective effects of yeast extracellular polysaccharides and glycoproteins.

Eighteen yeast strains were tested for their ability to survive the freeze-thaw process while being cryoprotected. Cryoprotection was accomplished by combining penetrating and nonpenetrating cryoagents. Four nonpenetrating (two extracellular polysaccharides of yeast and two extracellular glycoproteins of yeast) and two penetrating agents were used together with the nutritive-rich medium. Eight different mixtures were tested. The highest survival rate was obtained with glycoproteins of Rhodosporidium toruloides together with DMSO and nutritive-rich medium.

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.

Storage of Candida albicans, C. tropicalis and related species in liquid nitrogen.

Storage in liquid nitrogen of a collection of C. albicans, C. tropicalis and related species checked by numerical and classical taxonomy is described. Strains stored for 3 years in liquid nitrogen were thawed and their survival was tested. After adaptation and regeneration, their fermentation and assimilation spectra, production of chlamydospores and pseudomycelia, appearance and radial growth rate of giant colonies were investigated and compared with the properties of cultures stored under paraffin oil. It follows from the results obtained that two different media--with an increased content of a nitrogen source and with an increased carbon source content--should be used for the post-heating adaptation and regeneration of yeast cells. In some strains it is useful to store them at 4 degrees C for additional time intervals in order to increase survival of the cells. The above strains can be successfully stored in liquid nitrogen.