Showing papers on "Arabitol published in 2000"

Solute stresses affect growth patterns, endogenous water potentials and accumulation of sugars and sugar alcohols in cells of the biocontrol yeast Candida sake.

Abstract: Aim: To evaluate the effect of modifications of water activity (a(w) 0.996-0.92) of a molasses medium with different solutes (glycerol, glucose, NaCl, proline or sorbitol) on growth, intracellular water potentials (psi(c)) and endogenous accumulation of polyols/sugars in the biocontrol yeast Candida sake. Methods and Results: Modification of solute stress significantly influenced growth, psi(c) and accumulation of sugars (glucose/trehalose) and polyols (glycerol, erythritol, arabitol and mannitol) in the yeast cells. Regardless of the solute used to modify a(w), growth was always decreased as water stress increased. Candida sake cells grew better in glycerol- and proline-amended media, but were sensitive to NaCl. The psi(c) measured using psychrometry showed a significant effect of solutes, a(w) and time. Cells from the 0.96 a(w) NaCl treatment presented the lowest psi(c) value (-5.20 MPa) while cells from unmodified media (a(w) = 0.996) had the highest value (-0.30 MPa). In unmodified medium, glycerol was the predominant reserve accumulated. Glycerol and arabitol were the major compounds accumulated in media modified with glucose or NaCl. In proline media, the concentration of arabitol increased. In glycerol- and sorbitol-amended media, the concentration of glycerol rose. Some correlations were obtained between compatible solutes and psi(c). Conclusions and Significance: This study demonstrates that subtle changes in physiological parameters significantly affect the endogenous contents of C. sake cells. It may be possible to utilize such physiological information to develop biocontrol inocula with improved quality.

Different mechanisms of the biochemical adaptation of mycelial fungi to temperature stress : Changes in the cytosol carbohydrate composition

Abstract: The effect of temperature stress on the cytosol carbohydrate composition of fungi belonging to various systematic groups was investigated. In Mucorales representatives (subkingdom Eomycota, phylum Archemycota, class Zygomycetes), adaptation to hypo- and hyperthermia occurs via the regulation of trehalose synthesis, although inositol is also involved in these processes in Blakeslea trispora. Basidiomycota (subkingdom Neomycota) use two pathways of biochemical adaptation, depending on the cytosol carbohydrate composition. In the absence of sucrose, glycerol and arabitol are involved in the adaptation to hyperthermia; trehalose accumulates under hypothermic conditions (type I of regulation). Type II regulation (revealed in Pleurotus ostreatus) involves sucrose rather than glycerol or arabitol. The data obtained are discussed in terms of fungal systematics and phylogeny.

Alterations in the carbohydrate composition of the cytosol of fungal spores caused by temperature variations and the storage process

Abstract: Differences in the carbohydrate composition were revealed among spores of fungi belonging toZygomycetes, Ascomycota, Basidiomycota, andOomycota, part of the novel kingdomChromista. It was shown for the first time thatPhytophthora infestons contains arabitol in addition to glucose and trehalose. Sucrose was detected inPleurotus ostreatus basidiospores. It was established thatBlakeslea trispora stylospores contain inositol. The dependence of the spore carbohydrate composition on the temperature of the habitat of the corresponding species is discussed. It was shown that the cytosol of the conidia is dominated by trehalose and inositol under hypothermic conditions and by mannitol and glucose under hyperthermic conditions.Neomycota andEomycota were shown to differ in their responses to stress (starvation), which correlated with the differences in the carbohydrate composition of the spore cytosols. Assuming that cytosol carbohydrates perform a protective function, we explain the higher viability of conidia compared to stylo- and sporangiospores.

Process for the production of arabitol by continuous fermentation

Abstract: Production of arabitol (I) comprises continuous fermentation of sugar(s) in two successive fermentation zones with sugar addition to just the first zone. Production of arabitol (I) by continuous fermentation of sugar(s) with (I)-producing microorganisms comprises: (a) conducting production of (I) in a first fermentation zone (Z1), comprising at least one fermenter, in such a way that p of the sugar added to the fermentation medium is consumed by the microorganisms; (b) transferring part of the fermentation medium from Z1 to a second fermentation zone (Z2), comprising at least one fermen while maintaining constant volume in Z1 by adding sugar; (c) continuing production of (I) in Z2 so that the residual sugar in the fermentation medium is consumed; and (d) continuously separating the fermentation medium from Z2 into a concentrated microorganism fraction and a (I)-rich solub fraction.

Changes in the carbohydrate composition of cytosol from fungal spores in connection with environmental temperature and during storage

Abstract: Differences in the carbohydrate composition were revealed among spores of fungi belonging to Zygomycetes, Ascomycota, Basidiomycota, and Oomycota, part of the novel kingdom Chromista. It was shown for the first time that Phytophthora infestans contains arabitol in addition to glucose and trehalose. Sucrose was detected in Pleurotus ostreatus basidiospores. It was established that Blakeslea trispora stylospores contain inositol. The dependence of the spore carbohydrate composition on the temperature of the habitat of the corresponding species is discussed. It was shown that the cytosol of the conidia is dominated by trehalose and inositol under hypothermic conditions and by mannitol and glucose under hyperthermic conditions. Neomycota and Eomycota were shown to differ in their responses to stress (starvation), which correlated with the differences in the carbohydrate composition of the spore cytosols. Assuming that cytosol carbohydrates perform a protective function, we explain the higher viability of conidia compared to stylo- and sporangiospores.