Publications by authors named "Kolarova N"

An extracellular galactoxylomannan (GalXM) composed of D-Gal (34.0%), D-Xyl (26.6%) and D-Man (31.

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Conditions for conidiation of a natural isolate of Trichoderma atroviride during submerged cultivation in Erlenmeyer flasks and in a laboratory stirred-tank fermenter were optimized. From the simple sugars tested, cellobiose was the best substrate for conidia production while cellulose fines from paper mill waste proved to be a suitable cheap complex carbon source. Optimum temperature for conidiation was 24-26 degrees C, and the required dissolved oxygen level was > 40% saturation.

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The changes of molecular size of hyaluronan during enzymatic reaction of bovine testicular hyaluronidase at different conditions are monitored by size exclusion high performance liquid chromatography. The effect of glucuronate, galacturonate, glucosamines and pyridoxin as potential inhibitors of hydrolysis is evaluated. The most effective of all tested inhibitors was the presence of glucuronate which not only inhibited the hydrolysis, but also initiated enzymatic reconstruction by transglycosylation reaction at pH 7.

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Polysaccharide hydrolase activity was assayed in a group of 28 selected Rhizopus strains. The production of lichenases, mannanases, cellulases, xylanases, amylases and pullulanases was demonstrated using the gel-testing method during growth of the strains on suitably meshed polysaccharide gels.

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The possibility of using 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP) for activation of saccharide hydroxyl groups (instead of hazardous cyanogen bromide) is examined with cell-surface mannans of the yeasts Candida albicans, Candida tropicalis, Candida lambica and galactoglucoxylomannan of Cryptococcus laurentii. Direct conjugation with human serum albumin yielded soluble products with increased molecular size in comparison with the original polysaccharides. Immunodiffusion experiments revealed that conjugation did not affect the immunospecificity of the antigen epitppe.

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Comparisons of known primary structures of polygalacturonases show that extent and localization of potential N-glycosylation sites differ. Some sites are similar in position and adjacent to strictly conserved residues at the potential active site. The presence of N-acetylglucosamine and mannose in the molecules of two homogeneous, major Aspergillus sp.

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Using indirect methods based on uptake of [3H]tetraphenylphosphonium cation and [14C]benzoic acid by cells of the fungus Trichoderma viride we found that the illumination-induced transient hyperpolarization of the plasma membrane is followed immediately by a rapid temporary decrease in intracellular pH. Hyperpolarization and intracellular acidification were completely suppressed by 150 mM-KCl and by the K(+)-ionophore valinomycin. The light-induced acidification of the cytoplasm was not observed in the presence of the cytochrome respiratory chain inhibitors antimycin A and mucidin.

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The op1 mutation in yeast is known to be due to a defect in the mitochondrial ADP/ATP translocator. Sequencing of the gene AAC2 revealed that the mutation resulted from a single base change that caused a replacement of arginine 97 by a histidine. The gene encoding AAC2 was also cloned and sequenced from an op1 revertant capable of growth on glycerol as a sole carbon source.

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When illuminated by visible light, cell-free extracts from the fungus Trichoderma viride catalysed the phosphorylation of at least two proteins with molecular masses of 18 and 114 kDa which were practically absent when the phosphorylation was performed in the dark. The effect of light could be substituted by 3mM cyclic AMP, not only in the cell-free extract, but also in the separated cytosol. It is concluded that the process of photoinduced conidiation in Trichoderma involves phosphorylation of conidiation-specific proteins by (a) cyclic AMP-dependent protein kinase(s) present in the cytosol.

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