G mL21 of 49, 6diamidino-2-phenylindole (DAPI) in 75 ethanol for 1 hr to allow examination of the cell nuclei. Photographs were taken by fluorescence microscopy (IX70, Olympus, Tokyo, Japan). At least three independent experiments were performed.Detection and quantification of ganoderic acids by HPLCExtraction and detection of ganoderic acids (GAs) from the fungal mycelium was performed as previously described [17]. Dried mycelium (100 mg) was extracted with methanol, and GAs in supernatant was analyzed by HPLC. Lanosta-7,9(11), 24-trien3a-o1-26-oic acid (ganoderic acid 24) was used to construct a calibration curve for production of GA24 and total GAs in the fungal mycelium [17]. Total GAs produced by the fungal mycelium was calculated by adding the peak areas of compounds 3687-18-1 web eluted from 5 to 50 min by HPLC analysis [17].Expression of the genes encoding a squalene synthase and a lanosterol synthaseDNA fragments encoding a putative squalene synthase (SQS) and a putative lanosterol synthase (LS) were amplified from G. lucidum BCRC 36111 [17]. Northern blotting analysis was performed using standard procedures. Fungal total RNA was extracted by Trizol reagent (Castanospermine chemical information Invitrogen, Carlsbad, CA, USA). Digoxigenin-11-dUTP (Roche Applied Science) was incorporated into the SQS DNA by PCR using the primers glssF263 (59TGGACACGATCGAAGATGACATGAC39) and glssR1492 (59GCCATCGTTTGTGGGATCGCACAGAA39). A DNA probe specifically hybridizing to the LS sequence was amplified in a similar way using the primers gllsF1292 (59CGGCGTATCGGCACCAGACGAA39) and gllsR2105 (59TTCGGGTACGATATCGCGACGTTC39). Immunological detection of the Northern Blots using CDP-Star chemiluminescent substrate was conducted following the manufacturer’s recommended procedures (Roche Applied Science). All experiments were conducted at least three times.Materials and Methods The fungal strain and its culture conditionsThe BCRC 36111 strain of Ganoderma lucidum was purchased from the Bioresource Collection and Research Center (Hsin Chu, Taiwan). The fungus was maintained on potato dextrose agar (PDA; Difco, Sparks, MD, USA) plate at 28uC. Fungal mycelium grown on PDA overlaid with a layer of cellophane for 7 to 10 days at 28uC was used as inoculum. To test the effect of aspirin on GA production and biomass production, fungal mycelium (8.75 g) obtained from a 7?0 day-old culture was dispersed in sterile water (50 mL) using a sterile blender. Fungal mycelium of 70 mg was spread onto PDA (9-cm diameter petri dish) with a layer of sterile cellophane for 4?2 days at 28uC. Fungal mycelium was then transferred to 25-mL of PDB in a 250 mL flask and treated with aspirin for 6 to 48 hr with shaking (100 rpm) at 28uC. Fungal mycelium was then harvested, dried, weighted, and subjected for GA extraction. To evaluate GA and biomass production of fungal culture on PDA, fungal mycelium of 70 mg was applied to PDA with a layer of sterile cellophane for 1 to 6 weeks at 28uC. Fungal mycelium was then peeled from the cellophane layer to determine biomass and GA production. All treatments were carried using at least three replicates and were repeated at least 3 times.Detection of ROS generationThe accumulation of reactive oxygen species (ROS) in fungal cells was detected by 29,79-dichlorofluorescin diacetate (DCFHDA). Fungal mycelium that had been cultured on PDA for 2 days was pre-treated with 10 mM DCFH-DA for 1 hr in H2O. Aspirin at concentrations ranging from 1 mM to 8 mM was then incubated with mycelium for 4 hr. Photog.G mL21 of 49, 6diamidino-2-phenylindole (DAPI) in 75 ethanol for 1 hr to allow examination of the cell nuclei. Photographs were taken by fluorescence microscopy (IX70, Olympus, Tokyo, Japan). At least three independent experiments were performed.Detection and quantification of ganoderic acids by HPLCExtraction and detection of ganoderic acids (GAs) from the fungal mycelium was performed as previously described [17]. Dried mycelium (100 mg) was extracted with methanol, and GAs in supernatant was analyzed by HPLC. Lanosta-7,9(11), 24-trien3a-o1-26-oic acid (ganoderic acid 24) was used to construct a calibration curve for production of GA24 and total GAs in the fungal mycelium [17]. Total GAs produced by the fungal mycelium was calculated by adding the peak areas of compounds eluted from 5 to 50 min by HPLC analysis [17].Expression of the genes encoding a squalene synthase and a lanosterol synthaseDNA fragments encoding a putative squalene synthase (SQS) and a putative lanosterol synthase (LS) were amplified from G. lucidum BCRC 36111 [17]. Northern blotting analysis was performed using standard procedures. Fungal total RNA was extracted by Trizol reagent (Invitrogen, Carlsbad, CA, USA). Digoxigenin-11-dUTP (Roche Applied Science) was incorporated into the SQS DNA by PCR using the primers glssF263 (59TGGACACGATCGAAGATGACATGAC39) and glssR1492 (59GCCATCGTTTGTGGGATCGCACAGAA39). A DNA probe specifically hybridizing to the LS sequence was amplified in a similar way using the primers gllsF1292 (59CGGCGTATCGGCACCAGACGAA39) and gllsR2105 (59TTCGGGTACGATATCGCGACGTTC39). Immunological detection of the Northern Blots using CDP-Star chemiluminescent substrate was conducted following the manufacturer’s recommended procedures (Roche Applied Science). All experiments were conducted at least three times.Materials and Methods The fungal strain and its culture conditionsThe BCRC 36111 strain of Ganoderma lucidum was purchased from the Bioresource Collection and Research Center (Hsin Chu, Taiwan). The fungus was maintained on potato dextrose agar (PDA; Difco, Sparks, MD, USA) plate at 28uC. Fungal mycelium grown on PDA overlaid with a layer of cellophane for 7 to 10 days at 28uC was used as inoculum. To test the effect of aspirin on GA production and biomass production, fungal mycelium (8.75 g) obtained from a 7?0 day-old culture was dispersed in sterile water (50 mL) using a sterile blender. Fungal mycelium of 70 mg was spread onto PDA (9-cm diameter petri dish) with a layer of sterile cellophane for 4?2 days at 28uC. Fungal mycelium was then transferred to 25-mL of PDB in a 250 mL flask and treated with aspirin for 6 to 48 hr with shaking (100 rpm) at 28uC. Fungal mycelium was then harvested, dried, weighted, and subjected for GA extraction. To evaluate GA and biomass production of fungal culture on PDA, fungal mycelium of 70 mg was applied to PDA with a layer of sterile cellophane for 1 to 6 weeks at 28uC. Fungal mycelium was then peeled from the cellophane layer to determine biomass and GA production. All treatments were carried using at least three replicates and were repeated at least 3 times.Detection of ROS generationThe accumulation of reactive oxygen species (ROS) in fungal cells was detected by 29,79-dichlorofluorescin diacetate (DCFHDA). Fungal mycelium that had been cultured on PDA for 2 days was pre-treated with 10 mM DCFH-DA for 1 hr in H2O. Aspirin at concentrations ranging from 1 mM to 8 mM was then incubated with mycelium for 4 hr. Photog.