Synthesis of β‐glucans in Prototheca zopfii

Abstract

Membrane preparations from the non-photosynthetic alga Prototheca zopfii incorporate glucose from UDP-[3H]glucose into the trichloroacetic-acid-insoluble fraction and the polysaccharides insoluble in hot alkali. Time course and pulse-chase experiments indicate that the acid-insoluble fraction was a precursor of the alkali-insoluble fraction. Isolation of 3H-labeled membrane or soluble fraction showed that only membrane fractions were able to transfer radioactivity into polysaccharides. Treatment of glucosylated membranes with trypsin or cellulase only partially affect their transfer ability, indicating that the precursor was internalized in vesicles.Analysis of the in vitro synthesized polysaccharides by enzymatic and acid hydrolysis showed that glucose and cellobiose were present as radioactive sugars. Permethylation of the polysaccharide indicates that 80% of the glucose was /?-1,4-bonded with 20% in @-1,3-linkages. This polysaccharide was found to be identical with the cell- [6] and potato tuber [7]. This glucosylated protein is considered to be the first step in the biosynthesis of glycogen and starch. It has been suggested [8] that protein primer may be a universal requirement for the synthesis of polysaccharides, including cell-wall polysaccharides.The formation of protein-linked oligosaccharides that play an analogous role in structural /?-glucan polysaccharide synthesis was detected in bacteria [9], algae [lo], fungi [ll] and higher plants [12]. Incubation ofmung-bean membrane preparations with radioactive UDP-Glc resulted in the formation of some radioactive products, one of which was identified as a glucoprotein [12]. The conversion of the glucoprotein into polysaccharides was indicated by pulse-chase experiments,

Identification of glucan-mannoprotein complexes in the cell wall of Candida albicans using a monoclonal antibody that reacts with a (1,6)- -glucan epitope

“…in Prototheca xopfii (Rivas & Pont-Lezica, 1987), and also recently in 5'. cerevisiae (Montijn e t al., 1994).…”

Prototheca wickerhamii in a dog with cutaneous, ocular and systemic manifestations and treatment with terbinafine

“…(1→3)-β- d -glucan has been identified as a component of P. zopfii (Rivas and Pont Lezica 1987), and there is one report of a positive result in a human who died from systemic P. zopfii (Takano and others 2014); however, there are no previous reports of this test in systemic cases of P. wickerhamii . In this case, serum (1→3)-β- d -glucan was negative.…”

“…Serum testing for (1→3)‐β‐ d ‐glucan, a polysaccharide component of the cell wall in most fungal species, is a non‐invasive tool that can be used to identify invasive fungal infections. (1→3)‐β‐ d ‐glucan has been identified as a component of P. zopfii (Rivas and Pont Lezica 1987), and there is one report of a positive result in a human who died from systemic P. zopfii (Takano and others 2014); however, there are no previous reports of this test in systemic cases of P. wickerhamii . In this case, serum (1→3)‐β‐ d ‐glucan was negative.…”

A “Kelp-Like” Microorganism Within the Belly

“…hydrocarbonea (99% identical, 537 nucleotides/540; 100% query cover; GenBank accession number issued: MF421524). Prototheca zopfii was shown in vitro to contain approximately 10% glucose residues that are (1,3)-β-linked in the polymerized oligosaccharides of its cell wall [3], which is likely the reason why measurement of (1, 3)-β-D-glucan antigen was positive in the patient's blood [4].…”