Wi Young Lee

Ergothioneine Contents in Fruiting Bodies and Their Enhancement in Mycelial Cultures by the Addition of Methionine

Abstract The levels of ergothioneine (ERG), which have been shown to act as an excellent antioxidant, were determined in both fruiting bodies and mycelia of various mushroom species. We found that ERG accumulated at different levels in fruiting bodies of mushrooms and showed up to a 92.3-fold difference between mushrooms. We also found that ERG accumulated at higher levels in mycelia than in fruiting bodies of economically important mushroom species such as Ganoderma neo-japonicum, G applanatum and Paecilomyces tenuipes. The addition of 2 mM methionine (Met) to mycelial culture medium increased the ERG contents in most mushroom species tested, indicating that Met is a good additive to enhance the ERG levels in a variety of mushroom species. Taking these results into consideration, we suggest that the addition of Met to the mycelial culture medium is an efficient way to enhance the antioxidant properties in economically important mushroom species.

Induction and Growth of Vegetative Stems through In Vitro Culture of Gastrodia elata

S : Gastrodia elata has been cultivated as an important medicinal resources to treat various human diseases. One of the major problems associated with its field production is the degeneration of seed tubers, which is mainly caused by soil-borne pathogens. This study was conducted to produce disease-free seed tubers by the development of in vitro micro- propagation method. First, tubers of G. elata were treated with HgCl2 prior to culturing in vitro. Among various culture medium tested, water agar (WA) and WPM medium were the most effective on the induction and growth of vegetative stems. NAA (0.1 ㎎/l ) or TDZ (1.0 ㎎/l ) in WA medium showed better growth of vegetative stems compared to other plant hormones. Finally the induction and growth of vegetative stems were better in the dark compared to the light condition. In this study, we established an in vitro micropropagation system of G. elata, which might be an efficient way to increase the yield and quality of G. elata tubers in the field production.

Improvement of Ergone Production from Mycelial Culture of Polyporus umbellatus.

Ergone, a fungal metabolite derived from ergosterol, was previously isolated and identified from Polyporus umbellatus. Ergone is a major component of P. umbellatus known to have anti-aldosteronic diuretic effect and also displays cytotoxic activities. Most of mushroom’s fruit bodies used for test contained less than 10 μg/g of ergone. But P. umbellatus have larger amount of ergone than any other mushrooms. In order to improve the ergone production from the submerged culture of P. umbellatus, several factors including medium composition, culture conditions (temperature and pH) and different combinations of co-cultivation with various mycelia were studied. Among various carbon sources examined, starch proved to be most effective for the production of mycelia. The optimum pH and temperature for a flask culture of P. umbellatus mycelia were found to be 4.5 and 25°C, respectively. Under the optimized culture conditions, both the ergone production (86.9 μg/g) and mycelial growth (3.5 g/l) increased when P. umbellatus was cultured with Armillariella mellea. When the optimized conditions were applied, both mycelium and ergone production were significantly enhanced.

Quantitative effects of various tree species on tuber growth and pharmacological compositions of Gastrodia elata

Gastrodia elata is a myco-heterotrophic orchid that has been used in traditional medicine to treat number of human illnesses. It establishes symbiotic associations with compatible mycorrhizal fungi, such as Mycena species and Armillaria mellea, depending on its developmental stages. G. elata tubers contain two major pharmacological substances; gastrodin (GA) and ergothioneine (ERG). Here we investigated whether the use of different tree species could enhance the growth of G. elata tubers, or of the content of GA or ERG. A. mellea infected all 30 tree species but its infection levels varied among species. However, only 14 species stimulated the growth of G. elata immature tubers; Ulmus davidiana produced the biggest tubers (7.8 g FW) while Abies holophylla generated the least significant changes on the growth of tubers reaching their weights to 0.9 g. In contrast to the tuber growth, the infection levels of A. mellea in those trees were similar, indicating that the colonized levels of A. mellea on different tree hosts were not correlated with the yield of G. elata tubers. Interestingly, the weights of immature tubers developed on 14 tree species were negatively correlated with the levels of ERG, but not with those of GA. In conclusion, our study suggested that the use of U. davidiana instead of Quercus species, which has been used for traditional cultivation of G. elata, might enhance the yields of G. elata tubers, but reduce the ERG levels while maintaining the GA levels.

Estimation of acorn production capacity using growth characteristics of Quercus acutissima in a clonal seed orchard

Acorn production varies considerably among individual trees, years, and locations, which directly affect oak regeneration and populations of wildlife species. This study was conducted to estimate the acorn production capacities of trees in a clonal seed orchard (CSO) of Quercus acutissima by analyzing the relationship among morphological characteristics of acorns, growth characteristics of trees, and the number of acorns per tree in 9-year-old and 15-year-old trees, respectively. The age of the tree did not affect individual acorn morphological characteristics (weight, length, and width), but increased the mean acorn yield per tree from 1.26 kg at 9-year-old to 2.71 kg at 15-year-old. The number of acorns per tree showed strong positive correlations (P < 0.0001) with both crown width and crown volume of the tree. According to our equation, it was estimated that the management of tree density (to 180 trees per ha) and crown volume (to 78 m3) may have the maximum acorn production per ha. Therefore, our results suggested that optimal management of tree density and crown volume may be very effective in increasing the acorn production in CSO of Q. acutissima, which further provides an important initial step in establishing a governmental policy for seedling supply plans.