Antifreeze Activity of Xylomannan from the Mycelium and Fruit Body of <i>Flammulina velutipes</i>

Abstract

An identified class of antifreeze, a xylomannan-based thermal hysteresis TH -producing glycolipid, has been discovered from diverse taxa, including plants, insects, and amphibians. We isolated xylomannan from the mycelium and fruit body of the basidiomycete Flammulina velutipes using successive hot extraction with water, 2% and 25% aqueous KOH, and gel filtration chromatography. The xylomannan from the fruit body had a recrystallization inhibiting RI activity RI=0.44 at 0.5 mg/mL. The dried weight yield of the fruit body 7.7 10 -2 %, w/w was higher than that of the mycelium. Although the purified xylomannan from both soures were composed of mannose and xylose in a 2 : 1 molar ratio, the molecular weight of the xylomannan from the mycelium and fruit body was 320,000 and 240,000, respectively. The RI activity of mycelial xylomannan was higher than that from the fruit body RI=0.57 at 45 µg/mL. Although this RI activity was able to remain constant after exposure to various conditions, we confirmed that the decrease of RI activity was stimulated by the decrease of molecular weight that was caused by heating during the alkaline condition. The survival rate of the CHO cells at -20 for two days increased to 97% due to the addition of 20 µg/mL of purified xylomannan. This was the first report to indicate that xylomannan from the mycelium of Flammulina velutipes had a high level of ice recrystallization inhibiting activity like antifreeze proteins from plants and had rhe potential to become a new material for cell storage.

Composition and biosynthetic machinery of the Blumeria graminis f. sp. hordei conidia cell wall

“…Little is known about the role of xylose in the fungal cell walls. It could potentially be a component of xylomannan, which has been detected in the cell walls of Flammulina velutipes and Trichosporon cutaneum ( Depree et al, 1993 , Kawahara et al, 2016 ) and is found in diverse taxa, ranging from plants, insects, and amphibians ( Walters et al, 2011 ). Xylomannan has been proposed to act as an antifreeze molecule that enables organisms to overwinter.…”

Analysis of cell wall synthesis and metabolism during early germination of Blumeria graminis f. sp. hordei conidial cells induced in vitro

“…The presence of branched 1,4 xylosyl residues is novel and has not yet been reported in fungi. It was previously suggested that xylosyl residues in the Bgh cell wall may form xylomannan, an antifreeze molecule ( Pham et al, 2019 ), as xylomannan has been detected in the cell walls of other fungal species ( Walters et al, 2011 , Kawahara et al, 2016 ).…”

Antifreeze Water-Rich Dormant Cysts of the Terrestrial Ciliate Colpoda cucullus Nag-1 at −65 ℃: Possible Involvement of Ultra-Antifreeze Polysaccharides

“…Antifreeze molecules such as antifreeze proteins, polysaccharides such as xylomannan, and glycolipids have been found in various organisms that exhibit freezing tolerance (Walters et al 2009, Duman 2015, Kawahara et al 2016, Kim et al 2017. The freezing point of antifreeze proteins and xylomannan drops by at most 3−4℃ (Walters et al 2009, Kim et al 2017.…”