• Journal of Microbiology
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• v.34 no.1
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• pp.37-37
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• 1996

The internal regions of nuclear small subunit rRNA from 6 plaeurotus species and 5 Pleurotus ostreatus strains were amplified by PCR and sequenced. The DNA sequences of 8 Pleurotus strains (P. ostreatus NFFA2, NFFA4501, NFFA4001, KFFA4001, KFCC11635, P florida, P. florida, P. sajor-cuju, P. pulmonarius, and P. spodoleucus) were idential, but P. cornucopiae differed from them in two bases out of 605 bases. However, p[hylogenetic analysis of the sequences by DNA-distance matrix and UPGMA methods showed that P. ostreatus NFFA2m1 and NFFA2m2, known as mutants of P. ostreatus NFFA2, belonged to anther group of Basidiomycotina, which is close to the genus Auricularia. The difference of the SSU rDNA sequences of P. cornucopiae from other Pleurotus species tested corresponds to the difference of mitochondrial plasmid type present in Pleurotus species as observed by Kim et al. (1993, Korean J. Microbiol. 31, 141-147).ishement of silencing at the HMR/hsp82 locus can occur in G1-arrested cells. Cell cycle arrest at G1 phase was achieved by treatment of early log a cell cultures with .alpha.-factor mating pheromone, which induces G1 arrest. The result suggests that passage through S phase (and therefore DNA replication) is nor required for re-establishing silencer-mediated repression at the HMNRa/HSP82 locus. Finally, to test whether de nono protein synthesis is required for re-establishment of silencer-mediated repression, cells were pretreated with cycloheximide (500 /.mu.g/ml) 120 min. It was apparent that inhibiting protein synthesis delays, but does not prevent, re-establishment of silencer-mediated repression. Altogether, these results indicate that re-establishment of silencer-mediated repression is not dependent on the DNA replication and has no requirement for protein synthesis.

• Korean Journal of Microbiology
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• v.31 no.2
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• pp.141-147
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• 1993

Plasmid DNAs were detected from the mitochondrial fraction of four strains of whiterot fungus, Pleurotus ostreatus. The size of the plasmids were 10.2 and 7.2 kb in strain NFFA 2, 10.2 kb in NFFA 4001, 11.2 kb in NFFA 4501, and 10.2 and 11.2 kb in KFCC 11635. The two strains,NFFA 2ml and NFFA 2m2, which are mutant derivatives of NFFA 2, did not contain any plasmids. The cleavage by proteinase K indicated that these plasmids have DNA ends associated with proteins. In digestion with proteinase K all the plasm ids remained resistant to lambda exonuclease which hydrolyzes DNA from 5' ends and were sensitive to exonuclease III which hydrolyzes DNA from 3' ends. This suggests that the plasmids are linear double-stranded DNA and the terminal proteins are covalently linked to 5' ends of plasm ids. In order to find relationship between these plasmids, hybridization of plasm ids by each separate plasmid DNA was done. The result indicated that the plasmids can be classified into at least 3 groups. Plasmids of group I were present in all the P ostreatus. More mitochondrial plasmids were detected in P cornucopiae. P ,florida, P pulmonarius, P sajor-caju, and P spodoleucus. The size of plasmids ranged between 7.2 kb and 14 kb. All the species except P cornucopiae contained plasmids of approximately 10 kb which hybridized with the 10.2 kb plasmid (group I) of P ostreatus NFFA 2.

• The Korean Journal of Mycology
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• v.16 no.2
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• pp.87-94
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• 1988

Electrophoretic isozyme patterns from mycelia, primordia, cap and stem of Pleurotus spp. collected in Korea were compared. Primordia, cap and stem of fruitbody showed very similar isozyme patterns but mycelial isozyme patterns were different from those of fruitbody. Isozyme patterns of malate dehydrogenase, acid phosphatase in Pleurotus ostreatus collected from different regions in Korea were similar but those of esterase, peroxidase, leucine amino peptidase and superoxide dismutase were different. Interspecific comparison of esterase isozyme patterns among Pleurotus ostreatus P. cornucopiae and, P. florida was very different and may be valuable subsidiary tool to conventional taxonomic techniques for identifying species of Pleurotus. A dendrogram by similarities of isozyme band pattern was presented.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.200-211
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• 1993

Somatic hybrids of Pleurotus florida ASI 2016 and Pleurotus ostreatus ASI 2018 were obtained by protoplast fusion. The 40 fusants($P1{\sim}P40$) was examined for the yield on fermented and pasteurized rice straw in a tray. The carpophore yield of them were showed as the range of $27.0{\sim}155.2$, based on parental values of 100(ASI 2018), The pilei of fusants between orange white colored P. florida and dark grey colored P. ostreatus had mixed colors in the young stage. Other breeding programmes were performed to improve new varieties with high yield and good quality. A new oyster mushroom variety, Wonhyeongneutaribeosus(P72), was developed at the Agricultural Sciences Institute, Rural Development Administration in 1990. This P.florida-ostreatus-ostreatus hybrid P72 was selected from 38 protoplast fusion products($P41{\sim}P78$) between P.florida-ostreatus recombinant P5-M 43-arg rib and P. ostreatus ASI 2-13-0 2001-19-pro orn. The yield indexes of 38 hybrids ranged $40.5{\sim}152.7$ compared with the parental values of 100(ASI 2001). Hybrid P72 was characterized by the large fruiting bundle of semispherical shape with long stipe and by the small and circular pileus, resulting in lower harvesting cost. A significant increase in carpophore production was observed in somatic hybrids of protoplasts due to heterosis. A comparision of hybrid with parents P72 was made using isozyme analysis. The esterase banding patterns could be characterized by new bands in the hybrids. Seven fusion products of four crosses between P.florida ASI 2016 and P. ostreatus ASI 2018 were analysed with respect to the distribution of progenies and segregation of gene markers by random basidiospore analysis. Segregation of alleles should yield progeny of four genotypes in a Mendelian ratio of 1 : 1 : 1 : 1 for prototrophs, auxotrophs of one parental type, auxotrophs of the other parental type, and auxotrophic recombinants, respectively. However, five fusants of them did not detect one parental, P.ostreatus, type. Basidiospores could yield progeny of 16 genotypes in the cross of one of the recombinant P5-M43-arg $rib{\times}P. ostreatus$ ASI 2-13-pro orn but the segregants of three fusants were not detected clearly. The allele ratio of loci could be expected 1 : 1 : 1 : 1 for arg, rib, pro and orn. The ratio, however, would be changed to 4 : 1 : 1 : 1 with increasing proportion of argo In almost all the fusants, prototrophic recombinants were recovered in large numbers against auxotrophic markers. Parental genotypes were recovered with the recombinant progeny amounting to $38.68{\sim}99.56%$. The analysis provides proof of heterokaryosis and strong evidence for haploidy of vegetative nuclei, a sexual cycle consisting of nuclear fusion and meiosis.

• Mycobiology
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• v.36 no.4
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• pp.228-232
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• 2008

Mushroom cultivation has been started recently in Bangladesh. Awareness of the nutritional and medicinal importance of mushrooms is not extensive. In this study, the nutritional values of dietary mushrooms- Pleurotus ostreatus, Pleurotus sajorcaju, Pleurotus florida and Calocybe indica that are very popular among the cultivated mushrooms in Bangladesh have been determined. These mushrooms were rich in proteins ($20{\sim}25%$) and fibers ($13{\sim}24%$ in dry samples) and contained a lower amount of lipid (4 to 5%). The carbohydrate contents ranged from 37 to 48% (on the basis of dry weight). These were also rich in mineral contents (total ash content is $8{\sim}13%$). The pileus and gills were protein and lipid rich and stripe was carbohydrate and fiber-rich. The moisture content of mushrooms ranged from 86 to 87.5%. Data of this study suggest that mushrooms are rich in nutritional value.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.378-385
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• 1994

Interspecific somatic hybrids were obtained by protoplast fusion between Pleurotus ostreatus and Pleurotus sajor-caju. The fusion products between incompatible strains did not form clamp connections. Fruiting body of the clampless fusants was induced by light-dark cycle on saw-dust-rice bran substrate in glass bottles. Out of them, seven somatic hybrids produced fruiting bodies of intermediate morphology of the two species. Light and low temperature were the initiating factors for the development of clamped hyphae from the clampless mycelial colonies. All of these basidiocarps had clamp connections. Eight fusants from the six crosses were analysed with the segregation of genetic characters by random spore isolates. In the three combinations, unexpected alleles were shown. Somatic hybrid between P188 (P. ostreatus 2-1 + P. sajor-caju 2-53) and P. florida 2-3 by triple cross produced fruiting bodies similar to those of fusant between P. ostreatus and P. florida. All the genetic charaters from the three strains were shown to segregate and recombine.

• The Korean Journal of Mycology
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• v.15 no.4
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• pp.250-253
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• 1987

The transfer of the isolated nuclei from P. florida into protoplasts of P. ostreatus was induced with polyethylene glycol and $CaCl_2$. Three types of transfer products of nuclei were obtained when transferred to MMM. Type 1 colonies were more vigrously growing mycelium and stable on MCM. One of the type 1 colonies, appeared segregation on MCM plus benomyl. The mycelium did not form clamp connection. These results suggest that type 1 colonies were nuclear hybrids or allodiploids. Type 2 was main products of nuclear transfer. The mycelium formed clamp connection and fertile on sawdust media. Type 3 was very slow growing or non-viable colonies after debris of nuclei or chromosomes transfer into recipient protoplasts. Isozyme pattern of esterase in type 1 produced a new band. Type 2 and type 3 could be characterized by parental bands.

• The Korean Journal of Mycology
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• v.12 no.1
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• pp.1-8
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• 1984

The mycelial growth of some mushrooms was inhibited by benomyl treatment. The $ED_{50}$ of benomyl to that of Pleurotus spp., Agaricus bisporus and Flammulina velutipes was 25ppm, 50ppm and 200ppm, respectively, which indicates the former was the most sensitive to the fungicide. The mycelial growth of mushrooms growing on artificial media amended by benomyl was increased when they were cultured successively 5 times and 10 times on the media. The increasing rate of that of each mushroom was the highest at the concentration of $ED_{50}$ of benomyl. The mycelial growth of P. ostreatus was increased progressively as the number of successive culturing increased, while that of P. florida and A. bisporus was increased until they were cultured successively up to 5 times and 7 times, respectively, but they were decreased after that. Mutant sectors of mycelia were induced by successive treatment of benomyl. Mutant sectors of P. ostreatus appeared earlier than those of P. florida and all of them were induced earlier on the media of low contration of benomyl than on that of high concentration. The mycelia of mutant sectors induced by benomyl treatment grow faster than those of mother colony treated with benomyl successively, but there was no difference in resistance against the fungicide between them. The increase of mycelial growth of the mushrooms culturing successively on media containing benomyl indicated that they might obtain the resistance against benomyl.

• Journal of Mushroom
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• v.2 no.3
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• pp.115-126
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• 2004

Somatic hybrids of inter-compatible and inter-incompatible strains were obtained by protoplast fusion. The fusion products between compatible strains, Pleurotus ostreatus and P. florida, formed heterokaryons, while fusants between incompatible strains such as P. cornucopiae + P. florida, P. ostreatus + Ganoderma applanatum, P. florida + Ganoderma lucidum, and P. ostreatus + Flammulina velutipes formed synkaryons that retained genes from both parents. The heterokaryons showed the same level of basidioma development. In contrast, the synkaryons showed unique characteristics including clamp connection formation at mitosis, either partner basidioma development, and abnormal segregation and recombination compared with inter-compatible strains. Synkaryons can be classified into homokaryoyic and heterokaryotic type. A comparison of somatic hybrids with compatible and incompatible strains was made using random amplified polymorphic DNA (RAPD) analysis. The heterokaryons between compatible species showed the same level of variability and contained both parental RAPD bands. In contrast, most of the synkaryons between incompatible species showed similarity to those of either parental bands and non-parental RAPD bands. Synkaryons can be classified into microgenome insertion type and macrogenome insertion type. A tetrapolar mating system was found among monospore isolates in somatic hybrids and wild type P. ostreatus. Homokaryons from each somatic hybrid combination were paired with tester homokaryons of the initial wild type of P. ostreatus. The changed mating types were identified in progenies. The pattern of mating type switching in somatic hybrids depends on compatibility of fusion partner. There are several factors related to the mechanism of clamp connection formation and fruiting body development of synkaryons. Of these,the major factor may be associated with self-fertility and mating type switching such as homokaryotic fruiting of wild type P. ostreatus. This review will discuss these aspects.

• The Korean Journal of Mycology
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• v.12 no.4
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• pp.164-169
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• 1984

Interspecific heterokaryons were obtained between auxotrophic mutants of Pleurotus ostreatus and Pleurotus florida by polyethylene $glycol-Ca^{++}$ induced fusion of somatic protoplasts. The fusion products produced colonies of dense growing mycelium after 10-14 days culture on hypertonic Mushroom Minimal Medium. When they were transferred to Mushroom Minimal Medium plates, the sectors showed normal vegetative morphology but the colonies of irregular shape varied in growth rate. All of the colonies produced fruit body of normal pilei. Some heterokaryon colonies bearing none or only a small amounts of basidiospores were isolated. Fusion products, generally, gave higher basidiocarp yields than the parents.