Functionality and prevalence of trehalose‐based oligosaccharides as novel compatible solutes in ascospores of Neosartorya fischeri (Aspergillus fischeri) and other fungi

Abstract

Ascospores of Neosartorya, Byssochlamys and Talaromyces can be regarded as the most stress-resistant eukaryotic cells. They can survive exposure at temperatures as high as 85°C for 100 min or more. Neosartorya fischeri ascospores are more viscous and more resistant to the combined stress of heat and desiccation than the ascospores of Talaromyces macrosporus which contain predominantly trehalose. These ascospores contain trehalose-based oligosaccharides (TOS) that are novel compatible solutes, which are accumulated to high levels. These compounds are also found in other members of the genus Neosartorya and in some other genera within the order Eurotiales that also include Byssochlamys and Talaromyces. The presence of oligosaccharides was observed in species that had a relatively high growth temperature. TOS glasses have a higher glass transition temperature (Tg) than trehalose, and they form a stable glass with crystallizing molecules, such as mannitol. Our data indicate that TOS are important for prolonged stabilization of cells against stress. The possible unique role of these solutes in protection against dry heat conditions is discussed.

Decontamination of Aspergillus flavus and Aspergillus parasiticus spores on hazelnuts via atmospheric pressure fluidized bed plasma reactor

“…Many fungi belonging to the order Eurotiales, which includes the environmentally ubiquitous genera Aspergillus and Penicillium, form sexual ascospores that can survive high temperature (Dijksterhuis, 2007) and drought (Wyatt et al, 2015) and can exhibit other types of extreme stress resistance, and are therefore among the most resistant eukaryotic cells reported so far. For instance, ascospores of Neosartorya fischeri, a teleomorph of Aspergillus, survive 85°C in an aqueous environment for more than 10 min (Beuchat, 1986;Houbraken et al, 2012).…”

“…For instance, ascospores of Neosartorya fischeri, a teleomorph of Aspergillus, survive 85°C in an aqueous environment for more than 10 min (Beuchat, 1986;Houbraken et al, 2012). Moreover, in a dry state they survive a relative humidity lower than 0.5% at a temperature of 60°C for more than 7 days (Wyatt et al, 2015). These properties enable fungi such as N. fischeri to survive stress under adverse natural conditions including high temperatures during wet or dry conditions.…”

Structural analysis of novel trehalose-based oligosaccharides from extremely stress-tolerant ascospores of Neosartorya fischeri (Aspergillus fischeri)

“…46 We were able to isolate and characterize the DP3, DP4, and DP5 components of the oligosaccharide mixture, i.e. isobemisiose, neosartose, and fischerose, showing the extension of non-reducing trehalose on one side with (a1/6)-linked glucose residues as a recurrent theme.…”

“…46 Cell-free extracts were prepared after breaking of the ascospores by means of the Qiagen tissuelyser. 46 …”

“…Their possible biological function in terms of prolonged stabilization of cells against stress has been reported elsewhere. 46 …”