Studies on the polysaccharides of capsulated yeasts

Mager, J.

doi:10.1042/bj0410603

Cited by 35 publications

(4 citation statements)

References 18 publications

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“…Knowledge of the structures of the extracellular or intracellular polysaccharides of yeasts is sometimes useful in classification and identification of the parent organisms. For example, yeasts of the genus Rhodotorula form P-D-linked mannans (1) which distinguish them from Cryptococcus spp., which form starch and a heteropolysaccharide containing xylose, mannose, and glucuronic acid (2)(3)(4)(5)(6)(7). Previously the two genera were distinguished by the ability of Rhodotorula to form red, pink, orange, or yellow carotenoid pigments, but this criterion has been considered inadequate by Phaff and Spencer (8).…”

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confidence: 99%

Galactomannans of Trichosporon fermentans and other yeasts; proton magnetic resonance and chemical studies

Gorin¹,

Spencer²

1968

Can. J. Chem.

102

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A survey of the alkali soluble polysaccharides of yeast cells shows that galactomannans are formed by certain species of the genera Trichospororz, Schizosaccharomyces, and Nadsonia. Different species of Trichospororz form galactomannans, pentosylmannans, and a mannan. The galactomannans are distinguishable from those of Schizosaccharon~yces by the H-1 region of their proton magnetic resonance spectra (recorded at 70" in D 2 0 using an HA-100 Varian spectrometer), but the spectra of Trichospororz hellenicrrm and Nadsorzia fulvescer~s galactomannans are virtually indistinguishable.The proton magnetic resonance spectrum of the Trichosporor~ ferrner~tans galactomannan contains fewer signals than those of other Trichosporori galactomannans. The polymer consists predominantly of a main-chain containing a high proportion of (1 -> 6)-mannopyranosyl units substituted in their 2-positions by 0-a-D-galactopyranosyl-(1 -> 2)-0-a-D-mannopyranosyl side-chains (1).

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confidence: 99%

Galactomannans of Trichosporon fermentans and other yeasts; proton magnetic resonance and chemical studies

Gorin¹,

Spencer²

1968

Can. J. Chem.

102

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“…These results do not prove that the enzyme which synthesizes starch-like materials in vitro is the same as that performing such a function in vivo. However, the correlation is worth noting that certain organisms which synthesize starch or starchlike polymers in vivo have been shown to possess powerful phosphorylases in cell homogenates capable of synthesizing starch-like polymers upon incubation with glucose-1-phosphate (MACER 1947, LWOFF et al 1950. Furthermore, the decrease in phosphorylase level in "starch-deficient" mutants to about 25% of that of the wild type (Table 8), suggests a role for this enzyme in the process of amylose formation.…”

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confidence: 99%

Properties and kinetics of glucan phosphorylase of the amylose‐forming yeast Cryptococcus laurentii

Foda

Phaff

1978

J of Basic Microbiology

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1978 95-106(Eingegangen am 22.12.1976) Cell extracts of Cryptococcue laurentii, a yeast which synthesizes amylose when grown a t low pH, contained an a-glucan phosphorylase (a-1 -4)-glucan: orthophosphate glucosyl transferase (EC 2.4.1.1). The enzyme, which is very labile, showed greatest stability a t pH 8.0 in the presence of 0.1 M @-glycerophosphate and 0.1 M sodium fluoride. Based upon visible colour development with iodine a cell homogenate, centrifuged a t 32,000 g to remove cell debris, synthesized starch-like polymers upon incubation with glucose-1-phosphate in a p H range of 5.6-6.1. Based upon incorporation of labelled glucose from glucose-1-phosphate the pH of maximum activity was 5.9-6.2. The enzyme was partially purified by glycogen complexing, precipitation, and adsorption on hydroxylapatite followed by elution. The purified enzyme has a K, for glucose-lphosphate of 1.6 x lo-' M. Mutants impaired in their ability to synthesize amylose contained approximately one fourth of the phosphorylase activity as compared to the wild type. The possible role of the glucan phosphorylase in amylose biosynthesis is discussed.

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“…C. laurentii var. flavescens SCHULTZ AND ANKEL 0.1% urea, 0.1% KH2PO4, 0.05% MgSO4.H20, and 0.2 mg of thiamine hydrochloride per liter (14). The pH of this medium was 6.8.…”

Section: Methodsmentioning

confidence: 99%

Biosynthesis of Glycogen and Starch in Cryptococcus laurentii

Schultz

Ankel

1973

J Bacteriol

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Cells of Cryptococcus laurentii , when grown in liquid culture on 2% glucose close to neutral p H, showed glycogen granules throughout the cytoplasm. Glycogen levels of C. laurentii cells reached maximal levels just before onset of stationary phase. Concomitantly, a sharp rise in total and specific activity of glycogen synthetase was observed. Conversely, glycogen phosphorylase reached its highest specific activity approximately 3 hr after the glycogen peaked and remained high until most of the endogenous glycogen was utilized. Uridine diphosphoglucose pyrophosphorylase activity was always an order of magnitude higher than glycogen synthetase during log phase, but fell off rapidly after the cells reached stationary growth. Kinetic properties of the glycogen synthetase showed that the enzyme is always activated by glucose-6-phosphate, although the degree of activation by glucose-6-phosphate was found to be somewhat variable. The accelerated uptake of glucose commencing with the onset of stationary phase is explained by the rapid formation of extracellular acidic polysaccharide, which continues as long as there is glucose in the medium. In cells grown at p H 3.4, where no detectable extracellular acidic polysaccharide was formed, glucose uptake drastically declined when the cells reached stationary phase. These cells also contained glycogen-like granules in the cytoplasm. The evidence presented indicates that these granules are in fact glycogen, and that its structure does not resemble that of the starch excreted by cells grown at acidic p H.

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Studies on the polysaccharides of capsulated yeasts

Cited by 35 publications

References 18 publications

Galactomannans of Trichosporon fermentans and other yeasts; proton magnetic resonance and chemical studies

Galactomannans of Trichosporon fermentans and other yeasts; proton magnetic resonance and chemical studies

Properties and kinetics of glucan phosphorylase of the amylose‐forming yeast Cryptococcus laurentii

Biosynthesis of Glycogen and Starch in Cryptococcus laurentii

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