Unraveling the Polysaccharide Biosynthesis Potential of Ganoderma lucidum: A Chromosome-Level Assembly Using Hi-C Sequencing

Ganoderma lucidum exhibits the ability to synthesize a diverse range of biologically active molecules with significant pharmaceutical potential, including xylomannan and fucogalactan, which have demonstrated antitumor activity. However, there exists considerable intra-species variability in the capacity to produce these metabolites at high concentrations, likely reflecting the high genomic diversity observed from a limited number of strains sequenced to date. We employed high-throughput shotgun sequencing to obtain the complete genome sequence of G. lucidum strain 5.1, which is distinguished by its remarkable xylomannan synthesis capabilities. Through the utilization of semi-automatic reordering based on conformation capture (Hi-C) data, we substantially enhanced the assembly process, resulting in the generation of 12 chromosome-level scaffolds with a cumulative length of 39 Mbp. By employing both de novo and homology-based approaches, we performed comprehensive annotation of the genome, thereby identifying a diverse repertoire of genes likely involved in polysaccharide biosynthesis. The genome sequence generated in this study serves as a valuable resource for elucidating the molecular mechanisms underlying the medicinal potential of Ganoderma species, discovering novel pharmaceutically valuable compounds, and elucidating the ecological mechanisms of the species. Furthermore, the chromosome contact map obtained for the first time for this species extends our understanding of 3D fungal genomics and provides insights into the functional and structural organization within the fungal kingdom.

Antitumor and Antioxidant Properties of Water-Soluble Polysaccharides from Submerged Mycelium of Flammulina velutipes

The aim of the study was to evaluate antitumor and antioxidant properties of water-soluble polysaccharides from submerged myceliumn of Flammulina velutipes grown under optimized conditions. The optimization of the nutrient medium composition allowed to increase the biomass yield by more than 2 times (up to 35 g/l) and to reduce the time of the cultivation process. The submerged mycelium of F.velutipes strain Fv-1 contained 14.8% of a water-soluble polysaccharides, 31.6% of proteins, 2.5% of total lipids, vitamins B (B1, B5, B6). The polysaccharides contained glucose, galactose, fucose, mannose, xylose, rhamnose. The proteins contained all the essential amino acids except for tryptophan. Dry powder of the submerged mycelium, water extract of the mycelium and total fraction of the water-soluble polysaccharides demonstrated the antitumor activity against murine lymphocytic leukemia P 388 in vivo. The antitumor activity of the substances was mainly due to the polysaccharides, since their purification increased the tumor growth inhibition. The maximum tumor growth inhibition by the water-soluble polysaccharides amounted to 94%. The total fraction of the water-soluble polysaccharides from F.velutipes strain Fv-1 demonstrated antioxidant activity. The antioxidant capacity (AOC) of the water-soluble fraction from F.velutipes was higher than that of the water-soluble polysaccharides from the sub- merged mycelium of Grifolafrondosa, but inferior to the AOC of the water-soluble polysaccharides from the submerged mycelium of Ganoderma luciduma.

[Assessment of Antitumor Effect of Submerged Culture of Ophiocordyceps sinensis and Cordyceps militaris]

Ophiocordyceps sinensis and Cordyceps militaris metabolites showed a high potential in the treatment of tumors as well as some other diseases. Antitumor properties of O. sinensis and C. militaris submerged mycelium were investigated. It was found that the O. sinensis dry biomass in a dose of 50 mg/kg administered once a day to the mice with subcutaneously inoculated P388 lympholeucosis lowered the tumor growth by 65% vs. 54% for the C. militaris dry biomass. The water extract of O. sinensis submerged culture however accelerated the growth of the P388 lympholeucosis tumor node in the mice almost two times, compared to the control. A greater caution in using this fungus as a source of biologically active substances is required since unwanted tumor-stimulating effects can arise.

[Antitumor Activity of Polysaccharides from Ganoderma lucidum Mycelium: in vivo Comparative Study]

Fractions of water soluble and alkali soluble polysaccharides, as well as fucogalactan, a water soluble polysaccharide, and xylomannan, an alkali soluble polysaccharide, were isolated from the Ganoderma lucidum submerged mycelium. When administered orally, the polysaccharides showed antitumor activity in vivo on murine models of solid tumors. Xylomannan and fucogalactan showed the highest antitumor activity. Sensitivity to xylomannan was more pronounced in adenocarcinoma Ca755 as compared to the T-cell lymphocytic leukemia P388. The antitumor activity of the water soluble polysaccharides total fractions from the mycelium and fruiting bodies of the G. lucidum strain was almost identical. The maximum antitumor effect of the mycelium water soluble polysaccharides total fraction was observed with the use of the daily dose of 2 mg/kg.

[Antiviral properties of basidiomycetes metabolites]

The data on the antiviral action of the Ganoderma lucidum, Lentinus edodes, Grifola frondosa, Agaricus brasiliensis and other basidiomycetes metabolites are summurized. The metabolites of these species of basidiomycetes exhibit a direct antiviral effect on herpes simplex virus types I and II, human immunodeficiency virus (HIV), hepatitis B virus, vesicular stomatitis virus, influenza virus, Epstein-Barr virus, and others. Moreover, metabolites of basidiomycetes increased antiviral immunity.

Polysaccharides of basidiomycetes. alkali-soluble polysaccharides from the mycelium of white rot fungus Ganoderma lucidum (Curt.: Fr.) P. Karst

Two polysaccharides were isolated from submergedly cultured mycelium of the basidiomycete Ganoderma lucidum by extraction with alkali followed by fractionation with Fehling reagent. The polysaccharides were shown to be a linear (1-->3)-alpha-D-glucan and a highly branched xylomannan containing a backbone built up of (1-->3)-linked alpha-D-mannopyranose residues, the majority of which are substituted at O-4 by single beta-D-xylopyranose residues or by disaccharide fragments beta-D-Manp-(1-->3)-beta-D-Xylp-(1-->. Polysaccharide structures were elucidated by NMR spectroscopy in combination with methylation analysis and periodate oxidation. An interesting feature of the xylomannan is the simultaneous presence of alpha-D-mannopyranose and beta-D-mannopyranose residues, the first forming the backbone, and the second being the non-reducing terminal units of disaccharide side chains.