• The Korean Journal of Mycology
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• v.47 no.1
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• pp.63-73
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• 2019

Mycelial browning, which protects the organism from contamination and moisture loss, is essential for sawdust cultivation of Lentinula edodes. The effects of light and light wavelengths on the mycelial browning of the L. edodes Sanjo 701ho strain, and the characteristics of its brown hyphae, were investigated. After the mycelia were cultured on potato dextrose agar medium under fluorescent lamps covered with colored cellophane filters (red, green, and blue) or under light emitted diodes (LED), with wavelengths ranging from 400 to 700 nm (far-red, red, green, and blue), for 14 h per day for 40 days, the mycelial browning rate was measured. The wavelength of fluorescent lamps, which range from 300 to 1,100 nm, was reduced to 360 to 1,022 nm with the use of three colored cellophane filters and the photosynthetic photon flux density was reduced by 42 to 71 % depending on the light wavelength. The browning rate by colony area of mycelia exposed to light was at an average of 64 %, whereas, that of unexposed mycelia was only 5 %. The browning rate was 0.02 % in far-red, 1.5 % in red, 53.8 % in green, 57.3 % in blue, and 64.0 % in fluorescent light. The white mycelia were resilient with actively growing hyphae, filled with cytoplasm, and thin cell walls less than $1{\mu}m$ thick. Conversely, the brown mycelia possessed dead, hard hyphal structures without cytoplasm, but with approximately $2-4{\mu}m-thick$-thick cell walls. In conclusion, lights of varying wavelengths, especially short-wavelength LEDs, are effective for forming dead, brown mycelia of L. edodes, thus, forming a protective functional layer for its living white mycelia.

• The Korean Journal of Mycology
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• v.48 no.4
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• pp.389-396
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• 2020

Lentinula edodes is one of the most widely consumed edible mushrooms in Korea. Mating in L. edodes is regulated by a tetrapolar system, and two unlinked genetic loci, A and B, are known to be major determinants of the mating types, as reported in other heterothallic basidiomycetes. The A locus of L. edodes encodes a pair of homeodomain (HD) transcription factors. The highly variable N-termini of these HD transcription factors contribute to the diversity among the A mating types. In this study, we developed a cleaved amplified polymorphic sequence (CAPS) marker to discriminate 11 different A mating type alleles predominant among both cultivated and wild strains. Amplification of the variable region of the A locus followed by digestion with HaeIII and EcoRI restriction enzymes enabled successful discrimination among the 11 A mating type alleles. We also evaluated the applicability of this method in the identification of two A mating types of a dikaryotic strain.

• Journal of the Korean Wood Science and Technology
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• v.28 no.1
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• pp.48-54
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• 2000

The effects of thiamin on vegetative mycelial growth and fruit body formation of Lentinuia edodes were investigated in basal peptone-glucose liquid medium in relation to the uptake of thiamin. Thiamin was essential for fruit body formation, and the minimum requirements for thiamin were estimated to be approximately 10 ${\mu}g$/L. The vegetative mycelial growth was little influenced by the addition of thiamin in the range of 1.5 ${\mu}g$~1.5 mg/L. While the mycelium was successively transferred to fresh peptone-glucose-agar medium three times, the repression of mycelial growth was not significant. Even in cases using vitamin-free casamino acid or glutamic acid as a nitrogen source instead of peptone, a thiamin deficiency for mycelial growth did not occur as a result of transferring the mycelia to fresh media. Almost all of the thiamin contained in the media accumulated in the mycelia during the first 3 weeks of a 9-week incubation. These results suggest that only trace amounts of thiamin are required for vegetative mycelial growth in Lentinula edodes and that almost all thiamin added to a basal medium will be used for fruit body formation.

• 한국균학회소식:학술대회논문집
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• 2015.11a
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• pp.37-37
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• 2015

dsRNA was found in malformed cultures of Lentinula edodes strain FMRI0339, one of the three most popular sawdust cultivated commercial strains of shiitake, and was also found in healthy-looking fruiting bodies and actively growing mycelia. Cloning of the partial genome of the dsRNA revealed the presence of the RdRp sequence of a novel L. edodes mycovirus (LeV), and sequence comparison of the cloned amplicon showed an identical sequence to known RdRp genes of LeV found in strain HKA. The meiotic stability of dsRNA was examined by measuring the ratio of the presence of dsRNA among sexual monokaryotic progeny. More than 40% of the monokaryotic progeny still contained the dsRNA, indicating the persistence of dsRNA during sexual reproduction. Comparing the mycelia growth of monokaryotic progeny suggested that, although variations in the growth rate existed among progeny and virus infection was observed in highly actively growing progeny, there appeared to be a tendency toward a lower frequency of virus incidence in actively growing progeny. This study attempted to cure the edible mushroom L. edodes strain FMRI0339 of the L. edodes mycovirus (LeV) in order to obtain an isogenic virus-free fungal strain as well as a virus-infected strain for comparison. Mycelial fragmentation, followed by being spread on a plate with serial dilutions resulted in a virus-free colony. Viral absence was confirmed with gel electrophoresis after dsRNA-specific virus purification, Northern blot analysis, and PCR using reverse transcriptase (RT-PCR). Once cured, all of fungal cultures remained virus-free over the next two years. Interestingly, the viral titer of LeV varied depending on the culture condition. The titer from the plate culture showed at least a 20-fold higher concentration than that grown in the liquid culture. However, the reduced virus titer in the liquid culture was recovered by transferring the mycelia to a plate containing the same medium. In addition, oxygen-depleted culture conditions resulted in a significant decrease of viral concentration, but not to the extent seen in the submerged liquid culture. Although no $discernable phenotypic changes in colony morphology were observed, virus-cured strains showed significantly higher growth rates and mycelial mass than virus-infected strains. We were also explored effects of LeV on fruiting body formation and mushroom yield. The fruiting body formation yield of virus-free L. edodes was larger than virus-infected L. edodes. These results indicate that LeV infection has a deleterious effect on mycelial growth and fruiting body formation. In addition, we have been investigated host-parasite interaction between L. edodes and its mycovirus interaction to study viral mechanism by establishment of proteomics.

• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.115-124
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• 2009

New strain needs to maintain desirable characteristics for long term when it was bred, but in lapse of time it degenerates into a bad condition. Therefore the influence of temperature on the viability and survival rates of Lentinula edodes strains were examined after cryopreservation. Also, liquid nitrogen preservation for L. edodes has been proved to be one of the most reliable method. However, a mechanical damage of strain is inevitable during cryopreservation of the fungus because the fungus is very sensitive to stress of cooling rate in the freezing process. So we tried to find out state change of L. edodes with a programmable freezer. L. edodes strains were preserved at $-20^{\circ}C$, $-80^{\circ}C$ and $-196^{\circ}C$ for 50 days. At $-20^{\circ}C$, its mycelial growth became extinct. When thawed, the growth of mycelia which were preserved at $-80^{\circ}C$ was fastest. Attempts were made to investigate viability of L. edodes strains after freezing at $-80^{\circ}C$ and $-196^{\circ}C$, respectively. As the result, more than 90% showed high survival rate of strains tested at $-80^{\circ}C$ and $-196^{\circ}C$. Mycelial growth between apical and basal parts of colony after freezing preservation for 50 days was compared. At apical and basal parts, the survival rates showed 100% at $-80^{\circ}C$, but 98% and 94% at $-196^{\circ}C$, respectively. We confirmed that the ice crystal formation temperatures of L. edodes strains were $-6.0^{\circ}C$ for Sanlim 1, $-5.5^{\circ}C$ for the Sanlim 2, $-4.0^{\circ}C$ for the Sanlim 3 and $-15.5^{\circ}C$ for the Sanzo 302. These results indicated that L. edodes strains showed completely different responses to the ice crystal formation. We knew the fact that even the same species, especially L. edodes, they displayed completely different responses to the same freezing condition. Also, this has nothing to do with the connection between temperature type and freezing point. And a protocol was tried to minimize state change of L. edodes strains using programmable freezer when they are frozen, but it was not effective on them.

• Journal of Mushroom
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• v.19 no.3
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• pp.191-199
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• 2021

This study was conducted to improve the useful components and biological activity of Lentinula edodes fermented by lactic acid bacteria (LAB). Three LAB strains (Lactobacillus brevis KCCM 11904, L. plantarum KCCM 354469, and L. fermentum KCCM 12116) were inoculated and used for L. edodes hot water extract (10%, 20%, 30%) fermentation. LAB fermentation of L. edodes hot water extracts decreased pH and thus were more acidic than non-fermented L. edodes hot water extract. β-glucan and ergothioneine contents were increased by L. edodes in a concentration-dependent manner. The ergothioneine and β-glucan contents were highest in fermented with 30% L. edodes hot water extract fermented by L. plantarum and L. brevis (40.48 mg/100 g and 13.94%, respectively). The hepato-protective effect of fermented L. edodes hot water extracts by the three LAB were tested using Sprague-Dawley rat primary hepatocytes. In primary hepatocytes obtained following liver injury induced by acetaminophen, fermented L. edodes hot water extracts by the three LAB showed protective effects, as evident by reduction of the aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase liver markers. The collective results indicate that the fermented L. edodes hot water extracts obtained using LAB are potentially valuable in preventing or treating liver disease.

• Journal of Mushroom
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• v.18 no.4
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• pp.357-364
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• 2020

The grade and price of Lentinula edodes largely differs in preference depending on the product area and seasonal factors. The product amount of autumn L. edodes was higher than that of spring L. edodes, but high quality, which is divided into "Hwago" is low in preference. Mostly, the autumn L. edodes is obtained as powder; hence, it is necessary to develop a processing method to utilize its flavor and aroma at an affordable price. Additionally, we estimated the content of 𝛽-glucan, ergosterol, vitamin D₂, reducing sugars, and free amino acids and evaluated the anti-inflammatory activity of saccharification powder of log-cultivated L. edodes. In the saccharification powders obtained via 7 min of UV irradiation of log-cultivated L. edodes, 𝛽-glucan and vitamin D₂ contents were found to be the highest, whereas ergosterol content was found to be the lowest. The content of reducing sugars ranged from 62.4 mg/L to 68.2 mg/L. The free amino acids were higher in these saccharification powders than in the control. Subsequently, RAW 264.7 cells were treated with different concentrations (10, 50, 100, 200, 300, and 500 ㎍/mL) of the saccharification powders of log-cultivated L. edodes obtained via different UV irradiation time applications. The cells showed good viability; the anti-inflammatory effect was found to be the highest at 7 min UV irradiation. Therefore, 7 min of UV irradiation was determined to be the optimum condition for manufacturing saccharification powders of log-cultivated L. edodes. Hence, saccharification powders of log-cultivated L. edodes may be used as a raw material for natural sweeteners, food additives, and in the food industry.

• Journal of Applied Biological Chemistry
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• v.58 no.1
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• pp.25-29
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• 2015

The determination of the optimum conditions for the conversion of ergosterol to vitamin $D_2$ in shitake mushrooms (Lentinula edodes) was studied using response surface methodology (RSM). The effects of the three main variables ambient temperature ($20-40^{\circ}C$), exposure time (60-180 min), and irradiation intensity ($0.6-1.8W/m^2$) were investigated. According to the RSM ridge analysis, the optimum conditions were as follows: ambient temperature of $34.2^{\circ}C$, exposure time of 175.6 min, and irradiation intensity of $1.41W/m^2$. Under these optimum conditions, the maximum vitamin $D_2$ content of $117.93{\mu}g/g$ in shitake mushrooms was obtained, which agreed fairly well with the predicted value of $122.60{\mu}g/g$.

• The Korean Journal of Mycology
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• v.41 no.1
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• pp.28-32
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• 2013

New Shiitake (Lentinula edodes) strain "Chunbaegko" was bred by Di-mon method. Bed-log cultivation of "Chunbaegko" was performed. Fruit-body production of "Chunbaegko" was most at spring and autumn. Optimal temperature of fruit-body formation was $14{\sim}22^{\circ}C$ Baegwhako, the best quality fruit-body, is produced during spring. The diameter of pileus is ca. 52 mm. The total amount of fruit-body production during 4 years(one generation) was 140 $kg/m^3$ log.

• Korean Journal of Pharmacognosy
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• v.27 no.3
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• pp.224-230
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• 1996

To find pharmacologically active hybrids among the inter-order protoplast fusants of Lentinula edodes and Ginoderma lucidam the antitumor test was performed and the fusant P22 was selected among them. The hot water and alkaline extracts from the cultured mycelia of P22 were purified and separated into four fractions by DEAE-cellulose anion exchange chromatography. When a dose of 20 mg/kg/day of each fractions was injected into ICR mice by i.p., the tumor inhibition ratio of Fr. IV against solid sarcoma 180 was the higher than any other fraction. Fr. IV was a protein-bound polysaccharide which was composed of 69. 12% polysacchafide and 9.76% protein and the molecular weight of Fr. IV was $6.7{\times}10^4$ dalton.