Jong-Chun Cheong

Screening of Mushrooms Having Angiotensin I-Converting Enzyme Inhibitor

Extracts from 52 samples of mushrooms were prepared by using water, ethanol and methanol, and then yields and angiotensin I-converting enzyme(ACE) inhibitory activity were investigated. Sample mushrooms contained crude proteins of , curde lipids of and carbohydrates of . Among 52 samples, the water extract from fruiting body of Pholiota spp. ASI 24027 showed the highest extraction yield of 68%. Water extract of Pholiota spp. ASI 24012 fruiting body had potential ACE inhibitory activity of 66%. The optimal extraction condition of the ACE inhibitor from the fruiting bodyies of Pholiota spp. ASI 24012 was In water at for 1 hr and ACE inhibitory activity was 67.6% on the condition with 0.2 mg of .

Physico-chemical Characteristics and Utilization of Raw Materials for Mushroom Substrates

To provide a basic information on the chemical concentrations of different raw materials used in mushroom cultivation, the raw materials were collected from 13 Flammulina velutipes, 14 Pleurotus eryngii, and 8 P. ostreatus farms and analyzed to calculate moisture contents, pH, total carbon(T-C), total nitrate(T-N), total phosphate(T-P) and 13 different cations. In our results, the C : N ratios of cotton seed meal, beet pulp, and corn-cob were 6~17, 12~29 and 56~127, respectively. Depending on the companies which process these materials, the range of C:N ratio of soybean curd residue was approximately either 8~9 or 14~17 with wider range of C : N ratio of the raw materials imported from other countries without the detection of heavy metals. In this study, the formula was provided to calculate the composition of mixed media for mushroom cultivation based on the ingredient chart of different raw materials.

Characterization of Fruitbody Morphology on Various Environmental Conditions in Pleurotus ostreatus

This study investigated the morphological differences of P. ostreatus grown in the artificial environmental conditions such as humidity, temperature, ventilation, and watering. Oyster mushroom, which was cultivated on artificial environmental condition, was shown to have different morphology of fruitbodies. The optimum CO2 concentration for good morphology of P.ostreatus was 0.3%. But most fruitbody showed the morphologically low qualities in more than 0.5% of CO2 concentration. In the humidity in excess of 80% at 13~16°C, the best morphology of P. ostreatus was investigated. The growth of fruitbodies of P. ostreatus in the ventilation system was good at the wind velocity ranging from 0.2~0.5 fpms and expouring type. In other conditions, P. ostreatus generally showed the morphology closing to malformation.

Cultural Characteristics of Cauliflower Mushroom, Sparassis crispa

This study was carried out to obtain the basic data for the mycelial growth conditions of cauliflower mushroom, Sparassis crispa. Twenty-one isolates were collected from domestic and abroad. The optimal temperature and pH for the mycelial growth of these isolates were and pH 6.0, respectively. The mycelial growth was the best in the HBA medium, but very poor in the Lilly medium. However no mycelial growth in the CzapekDox medium. The utilization of carbon source was the best with fructose, and that of nitrogen source was the best with glutamine when compared to other tested sources. The selected isolate ASI150010 produced the highest mycelial weight in liquid culture containing soybean mill () and potato () extract. And uncleaned rice, wheat and barley were found to be good substrates for the mycelial growth S. crispa.

Effects of NaCl Concentrations on Production and Yields of Fruiting Body of Oyster Mushrooms, Pleurotus spp.

This studies investigated the effect of concentrations of sodium chloride (NaCl) on occurrence and growth of fruitbody in oyster mushrooms, Pleurotus spp. Our experiments divided into two parts. When the water contents in substrate were added with sodium chloride solution in cotton waste box cultivation as a first experiment, the growth of mushroom was damaged as the concentration was increased, even though there was a little difference according to the strains. The yield in 1.0% NaCl solution was decreased to 72% compared to non-treated plot while that in 3.0% solution was only 2% of the non-treated plot. Morphological characteristics of mushrooms cultivated in substrate with the different concentration of the solution showed different results. For example, the size and thickness of pilei were not influenced by NaCl concentration, but the length of stipes and individual weight were much influenced. In plastic box cultivation filled with cotton waste, watering treatment with the different concentrations of sodium chloride solution, the second experiment, did not show any difference according to the concentration until 1.0% solution but there was a little difference according to the strains. The productivity of fruitbody started to decrease at 2.0% of the solution and the yield and quality of mushroom in 3.0% solution treatment were generally low. After the second flush, days for mushroom sprouting were generally prolonged in proportion to the solution concentration. Taken altogether, the second experiment did not show a clear effect as the case of the first experiment.

Occurrence of black rot of cultivated mushrooms (Flammulina velutipes) caused by Pseudomonas tolaasii in Korea

From black spots on winter mushroom (Flammulina velutipes), fluorescent bacteria were repeatedly isolated during surveys at places of production in the years 2009–2010 in Korea. From these lesions three bacterial strains (designated CHM13, CHM16, CHM17) were isolated which, following inoculation of mushroom stipes and caps, yielded characteristic black spots and sunken lesions, which developed into a severe black rot. Results of Gram stain and biochemical tests preliminarily identified these isolates as Pseudomonas tolaasii. This was confirmed by pathogenicity to winter mushroom, physiological and biochemical properties, analysis of the 16S rRNA and rpoB gene sequences, fatty acids profile, specific and sensitive PCR assays and, lipopeptide detection. This is the first report of the isolation of Pseudomonas tolaasii from cultivated winter mushroom in Korea.

Genetic Diversity and Phylogenetic Relationship in Korean Strains of Lentinus lepideus Based on PCR Polymorphism

Lentinus lepideus, known as train wrecker fungus, has been used for nutritional and medicinal purposes. Recently, commercial cultivation technique and a new cultivar of the mushroom were developed. To investigate the genetic diversity and phylogenetic relationship for identifying the mushroom strains and cultivar, one commercial and 13 strains of Lentinus lepideus from different geographical regions of Korea were analyzed by ITS regions of rDNA and RAPD of genomic DNA. Three strains of Lentinus edodes were also used for the analysis. The size of the ITS1 and ITS2 regions of rDNA from the different strains varied from 173 to 179 bp and 203 to 205 bp, respectively. The sequence of ITS1 was more variable than that of ITS2, while the 5.8S sequences were identical with 156 base pairs. A phylogenetic tree based on the ITS region sequences indicated that selected strains could be classified into four clusters, while 3 strains of L. edodes was divided into a new cluster. Ten primers out of 20 arbitrary primers used in the RAPD-PCR efficiently amplified the genomic DNA. The numbers of amplified DNA bands varied with the primers and strains, with polymorphic DNA fragments in the range from 0.2 to 2.6 kb. The results showed that phylogenetic relationship among Korean strains of Lentnus lepideus is high, but genetic diversity is low.

Occurrence of Internal Stipe Necrosis of Cultivated Mushrooms (Agaricus bisporus) Caused by Ewingella americana in Korea

Abstract The internal stipe necrosis of cultivated mushrooms (Agaricus bisporus) is caused by the bacterium Ewingella americana, a species of the Enterobaeteriaeeae. Recently, Ewingella americana was isolated from cultivated white button mushrooms in Korea evidencing symptoms of internal stipe browning. Its symptoms are visible only at harvest, and appear as a variable browning reaction in the center of the stipes. From these lesions, we isolated one bacterial strain (designated CH4). Inoculation of the bacterial isolate into mushroom sporoearps yielded the characteristic browning symptoms that were distinguishable from those of the bacterial soft rot that is well known to mushroom growers. The results of Gram stain, flagellal staining, and biochemical tests identified these isolates as E. americana. This was verified by pathogenicity, physiological and biochemical characteristics, and the results of an analysis of the 16S rRNA gene sequences and the fatty acids profile. This is the first report of the isolation of li. americana from cultivated white button mushrooms in Korea.

Cultural Characteristics of Veiled Lady Mushroom, Dictyophora spp.

This study was carried out to obtain the basic data for artificial culture of veiled lady mushroom (Dictyophora spp). The optimal conditions for the mycelial growth were 25°C and pH 5.0 for all isolates except the optimal temperature of 30°C for D. echinovolvata ASI 32002 and Phallus rugulosus. The optimal medium for Dictyophora spp. was PBA (potato bamboo sawdust extract agar) medium. The strain ASI 32002, D. echinovolvata, grew faster than D. indusiata ASI 32003 and Phallus rugulosus ASI 25007 on the medium. Carbon sources such as glucose, maltose and inuline were favorable for stimulating a mycelial growth of the two strains of ASI 32002 and ASI 32003. Asparagine and glutamine appeared to be favorable to the strain ASI 32002 and ASI 32003, where as alanine, one of nitrogen source also favorable to the strain ASI 32002. The optimum C/N ratio of the two isolates of ASI 32002 and ASI 32003 was about 25:1 when 2% glucose as carbon source was mixed with the basal medium. While, in the case of 4% as carbon source, the optimum C/N ratio was about 30:1.

Characteristics and breeding of a new multi-generation oyster mushroom (Pleurotus ostreatus) variety 'Dagul'

To develop a new variety of oyster mushroom(Pleurotus ostreatus), parental strains was selected by the method of Mon-Mon crossing between monokaryotic strains derived from ASI 2596(Suhan No.3) and ASI 2782(Black pileus mutant). The SB-73(ASI 2596-11 x 2782-8) was shown the best cultural characteristics, selected to be a new variety and named as `Dagul`. The `Dagul` was formed incompatibility line distinctly in the confrontation growth of parental strains Suhan No.3 and ASI 2782. The optimum temperature for mycelial growth, fruiting body development and pH arrange were , and pH5~8, respectively. Fruiting body production per bottle was about g which is almost 115% quantity compared to that of other variety Suhan No.3. And also the stipe is long and individual generation is multiple. Analysis of the genetic characteristics of the new variety `Dagul` showed different DNA bands as that of the control strains, Suhan No.3 and ASI 2782, when RAPD(Random Amplified Polymorphic DNA) primers URP7 and Rcb1 were used. This new variety `Dagul` of oyster mushroom is characterized by multiple of individual generation and the stipe is long. We therefore expect that this new strain will increase of the income by cultivation of field.