Background
Polyporus umbellatus sclerotia have been used as a diuretic agent in China for over two thousand years. A shortage of the natural P. umbellatus has prompted researchers to induce sclerotial formation in the laboratory.Methodology/Principal Finding
P. umbellatus cultivation in a sawdust-based substrate was investigated to evaluate the effect of low temperature conditions on sclerotial formation. A phenol-sulfuric acid method was employed to determine the polysaccharide content of wild P. umbellatus sclerotia and mycelia and sclerotia grown in low-temperature treatments. In addition, reactive oxygen species (ROS) content, expressed as the fluorescence intensity of mycelia during sclerotial differentiation was determined. Analysis of ROS generation and sclerotial formation in mycelia after treatment with the antioxidants such as diphenyleneiodonium chloride (DPI), apocynin (Apo), or vitamin C were studied. Furthermore, macroscopic and microscopic characteristics of sclerotial differentiation were observed. Sclerotia were not induced by continuous cultivation at 25°C. The polysaccharide content of the artificial sclerotia is 78% of that of wild sclerotia. In the low-temperature treatment group, the fluorescent intensity of ROS was higher than that of the room temperature (25°C) group which did not induce sclerotial formation all through the cultivation. The antioxidants DPI and Apo reduced ROS levels and did not induce sclerotial formation. Although the concentration-dependent effects of vitamin C (5–15 mg mL−1) also reduced ROS generation and inhibited sclerotial formation, using a low concentration of vitamin C (1 mg mL−1) successfully induced sclerotial differentiation and increased ROS production.Conclusions/SignificanceExposure to low temperatures induced P. umbellatus sclerotial morphogenesis during cultivation. Low temperature treatment enhanced ROS in mycelia, which may be important in triggering sclerotial differentiation in P. umbellatus. Moreover, the application of antioxidants impaired ROS generation and inhibited sclerotial formation. Our findings may help to provide new insights into the biological mechanisms underlying sclerotial morphogenesis in P. umbellatus.
The germination rate and longevity of seeds of Gastrodia elata Blume have been observed for 48 weeks using Mycena osmundicola strain H-21, one of fungi stimulating seed germination. Storage condition of post-harvest seeds was observed in the different temperature ranges of -30℃, -5℃, 5℃ and 30℃ for 48 weeks. After storage period of 48 weeks, the germination rate of G. elata was 65.7% at 5℃ and 71.6% at -5℃, respectively. Although the germination rate of G. elata was 77.3% for 11 weeks at 25℃, the germination rate had been decreased gradually to 49.3% at 13 weeks, 0.3% at 23 weeks and then 0% at 25 weeks. The germination rate was reached to the level of 10% for 2 weeks at -30℃ and then decreased to 0%.
The caterpillar-shaped Chinese medicinal mushroom (DongChongXiaCao) looks like a worm in the winter and like a grass in the summer. The fruiting body has been regarded as popular folk or effective medicines used to treat human diseases such as asthma, bronchial and lung inflammation, and kidney disease. The fruiting bodies of Paecilomyces tenuipes that formed on the living silkworm (Bombyx mori) host were used in this examination. This study was carried out to investigate the proximate composition, soluble sugar, amino acid and fatty acid profiles, and contents of the bioactive ingredient including adenosine and D-mannitol in the fruiting-bodies. The moisture content was 57.56%. Soluble sugars found were glycerol, glucose, mannitol and sucrose, and the contents exceeded 24 mgg-1dry weight. Total free amino acid content was 17.09 mg g-1dry weight. Arginine, glycine, proline and tyrosine were main amino acids. The content of oleic acid in fatty acids was high. Adenosine was more abundant in fruiting bodies than corpus.
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