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Responses of mycelia of Ganoderma lucidum to vanadium, selenium and germanium were examined over a wide range of concentrations (10-1,120 pg/ml) in pure culture. Se and V were found to be highly toxic, but Ge was not toxic at the levels tested. Ganododerma lucidum cultivated on substrates of sawdust with V (30-80/~g/g) developed mature fruitbodies, but the bioaccumulation of V was quite low (2.5-7 pg/g in pileus, 12.5-21.5 Fg/g in stipe and < 1 ~g/g in basidiospores). Se as Na2Se04 labeled with 75Se was effectively taken up from substrates and accumulated in fruitbodies (mainly in pileus), then depleted by discharge of basidiospores. Ge as GeCI4 labeled with 77Ge was easily uptaken and translocated into fruitbodies.Key Words--accumulation; Ganoderrna lucidurn; germanium; selenium; vanadium.The trace elements in fungi are a neglected area of study, and data on responses of higher fungi to such elements are scant. For example, selenium (Se) has been studied sporadically in mycology for its distribution in fungal biomass and its effects on fungal growth and development. On the other hand, it is regularly reported to be present in bioactive antioxidants and to be an important microelement in foods, whose deficiency in the diet results in serious heart diseases (Ferretti and Levander, 1976 (Bao and Thuy, 1983). Although vanadium (V) is widely distributed in nature, particularly in sea ecosystems, data on V in fungi are very few, whereas its bioactivity in mammalian, namely, human cell lines and in medicine has been reported recently (Sabbioni et al., 1989).In some higher fungi, accumulation of V paralleled that of Se (Byrne and Ravnik, 1976). Mizuno et al. (1988), Tong andKhoong (1994), andFu (1996) have reported germanium traces in Ganoderma lucidum (W. Curt.: Fr.) Karst. fruitbodies grown under normal conditions on various substrates in Japan, Taiwan, and Malaysia. They attempted Ge-bioenrichment in mycelial fermentations and fruiting cultivations of G. lucidum on large scales in order * Nuclear Research Institute, No. 1 Nguyen Tu Luc St., Dalat, Vietnam. ** To whom correspondence should be addressed.to improve yields of compounds with biopharmacological activities in the products from this well-known medicinal fungus.In view of the biochemical importance of the toxic and beneficial actions of mineral elements in higher fungi, particularly medicinal mushrooms, we examined the responses of G. lucidum to about 30 elements that are commonly distributed in fruitbodies. Of these, V, Se and Ge were found only in trace levels in G. lucidum commonly cultivated in Dalat, Vietnam (Tham, 1996a, b). To elucidate further the physiological responses of G. lucidurn to bioactive elements, particularly their bioaccumulation, in order to improve the pharmacological qualities of the mushroom, we investigated the growth of mycelia and fruitbody formation of G. lucidum varieties on media supplemented with V, Se and Ge. Materials and MethodsThe newly found strains of G. lucidum in Dalat, Central Highlands of Vietnam (about 1,500 m above ...

The levels of seven heavy metals and their toxicity toward Ganoderma lucidum under various cultivation conditions were assessed. The contents of Mn, Cu, Zn, Cd, Hg, Pb and U in the fruitbodies of cultivated G. lucidum and sawdust substrates were determined to be at trace levels for U, 0.01-0.1 ~g/g for Cd and Hg, and 1-5/tg/g for Pb, 10-120/tg/g for Mn, Cu and Zn. The effects of heavy metals on the growth of mycelia of G. lucidum in pure cultures were examined over a wide range of concentrations (lO-3,000pg/ml), and their toxicities were found to decrease in the order: Hg>Cd>Cu>U>Pb>Mn=Zn.The translocation and accumulation of Zn from contaminated substrates (at 10/~g/g) in fruitbodies were investigated by using 6SZn tracer, and G. lucidum was found to take up Zn with an efficiency of >60%, leading to accumulation of > 100/~g/g in fruitbodies and >80 Fg/g Zn in basidiospores.

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Lentinula edodes is a favorable edible mushroom in the world. Its successful cultivation requires not only good and high yield strains but also the appropriate nutrient sources and environmental conditions. A hybrid strain (Len 003-009) is the result of the mating between a commercial strain (Japan) (Len 009) and a wild one (Langbiang mountain, Lam Dong) (Len 003). Studying some biological characteristics of the hybrid showed that its growth rate was similar to or quicker than that of the commercial strain and about twice as rapid as that of the wild one. The hybrid also represented some heredity characteristics from its parents. In addition, the optimal growth of the hybrid and the commercial strain were similar with the temperature from 24 to 27 degree Celsius, the concentration of glucose and peptone being 20 g/l and 1 g/l, respectively. Moreover, its parents could only optimally grow at the different levels of pH (pH=5 in Len 009 and pH=6 in Len 003), while the hybrid could do that in both mentioned levels. Again, this showed good characteristics of hybrid got from its parents. All strains did not have any demand for yeast extract during their growth and development. Thus, it could not evaluate whether there was any inheritance from its parents or not from this experiment.

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