• The Korean Journal of Mycology
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• v.52 no.1
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• pp.1-11
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• 2024

The present study aimed to screen unrecorded wild yeasts from Jeju lsland and Jangsado on the southern coast of Korea, and to investigate their microbiological characteristics. To date, Coniozyma leucospermi JJD37-2, Hanseniaspora thailandica JJD44-1, Kluyveromyces nonfermentans JJD15-1, Kockovaella fuzhouensis JJD47-3, Vishniacozyma heimaeyensis JJD8-4, Candida carpophila JSDH24-1, Wickerhamomyces strasburgensis JSDH34-2, Candida savonica HJD6-4, and Candida karawaiewii YP23-3 have not been previously recorded in Korea. In the present study, we investigated the microbiological characteristics of these previously unrecorded yeasts. Except for W. strasburgensis JSDH34-2 strain, none of the strains formed spores, and only the C. leucospermi JJD37-2 strain formed pseudomycelia. Almost all strains grew well in yeast extract-peptone-dextrose (YPD) medium, potato dextrose (PD) medium and yeast extract-malt extract (YM) media. C. carpophila JSDH24-1 and W. strasburgensis JSDH34-2 also grew well in YPD medium containing 10% NaCl. H. thailandica JJD44-1 is fermented to produce glucose, fructose and mannose.

• Journal of Plant Biotechnology
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• v.7 no.4
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• pp.259-265
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• 2005

Indian citrus ringspot virus (ICRSV)-free plants of Kinnow mandarin (Citrus nobilis Lour x C. deliciosa Tenora) were raised from virus-infected plants using unfertilised ovules as explants. Plants were tested by indirect ELISA and RT-PCR before using their explant. An amplified product of 539 bp was obtained by RT- PCR in ICRSV infected plants. Unfertilized ovules were excised from unopened flower buds of plants tested postive for virus and were cultured on Murashige and Skoog's (MS) basal medium supplemented with various concentrations of kinetin (KN) or malt extract (ME). Maximum induction (31.94%) of embryogenic callus was observed on MS medium supplemented with KN ($9.29\;{\mu}M$). Transfer of embryogenic calli to similar media composition resulted in somatic embryogenesis in all cultures, with an average number of 60.36 globular, 17.39 heart and 7.71 cotyledonary-shaped somatic embryos per culture. All cotyledonary shaped embryos developed into complete plantlets within 60 days on transfer to similar medium. Embryogenic callus induction, somatic embryo formation, maturation, germination and plantlet formation were achieved on MS medium supplemented with KN ($9.29\;{\mu}M$) alone. The plantlets derived from somatic embryos were transferred to sterilized soil, sand and vermiculite (3:1:1) mixture. After acclimatization, the plantlets were transferred to screen house and were indexed for ICRSV employing indirect ELISA and RT-PCR and found free of virus. A distinct feature of this study is the induction of somatic embryogenesis from unfertilised ovules to produce virus-free plants.

• Mycobiology
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• v.38 no.1
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• pp.17-25
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• 2010

The common split-gilled mushroom, Schizophyllum commune is found throughout the world on woody plants. This study was initiated to evaluate conditions for favorable vegetative growth and to determine molecular phylogenetic relationship in twelve different strains of S. commune. A suitable temperature for mycelial growth was obtained at $30^{\circ}C$. This mushroom grew well in acidic conditions and pH 5 was the most favorable. Hamada, glucose peptone, Hennerberg, potato dextrose agar and yeast malt extract were favorable media for growing mycelia, while Lilly and glucose tryptone were unfavorable. Dextrin was the best and lactose was the less effective carbon source. The most suitable nitrogen sources were calcium nitrate, glycine, and potassium nitrate, whereas ammonium phosphate and histidine were the least effective for the mycelial growth of S. commune. The genetic diversity of each strain was investigated in order to identify them. The internal transcribed spacer (ITS) regions of rDNA were amplified using PCR. The size of the ITS1 and ITS2 regions of rDNA from the different strains varied from 129 to 143 bp and 241 to 243 bp, respectively. The sequence of ITS1 was more variable than that of ITS2, while the 5.8S sequences were identical. A phylogenetic tree of the ITS region sequences indicated that the selected strains were classified into three clusters. The reciprocal homologies of the ITS region sequences ranged from 99 to 100%. The strains were also analyzed by random amplification of polymorphic DNA (RAPD) with 20 arbitrary primers. Twelve primers efficiently amplified the genomic DNA. The number of amplified bands varied depending on the primers used or the strains tested. The average number of polymorphic bands observed per primer was 4.5. The size of polymorphic fragments was obtained in the range of 0.2 to 2.3 kb. These results indicate that the RAPD technique is well suited for detecting the genetic diversity in the S. commune strains tested.

• The Korean Journal of Mycology
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• v.13 no.4
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• pp.221-224
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• 1985

The life cycle of 17 species of Trichoderma was elucidated to seize the proper stage for observing the nuclear behavior and chromosome count. The most convenient stage for the purpose in their life cycle was the stage just before producing the asexual spore. Of the 17 species in the genus Trichoderma the haploid chromosome numbers were counted 5,6,7 and 10. Six chromosomes were most frequently observed. It is believed that the basic chromosome number is placed between 4 and 10, and that the number might be 6, referring to the related papers. It appears necessary to reclassify the single genus of Trichoderma into at least two or three genera.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.16-19
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• 1996

The yeast strains isolated for Choungju brewing in the previous report were examined for their microbiological characteristics, together with some comparative tests with Japanese sake yeasts. The isolates KP-16, 21 and 54 were identified as the strains belong to Saccharomyces cerevisae according to the morphological and physiological properties described in Lodder's 'The Yeasts - A texanomic study'. The isolates were grouped into the pink-colored strains by 2,3,5-tripheny tetrazolium chloride over-lay method. The strains KP-16 and 21 were found to be distinguished from the strain KP-54 in aspects of fermentation of sugars, assimilation of carbon sources, and pellicle formation on malt extract broth. ${\alpha}-methyl-D-glucoside$ was not assimilated or fermented by the isolated yeast strains and this is one of the different characters from the Japanese sake yeasts. The isolated strains appeared to have the requirements for biotin and pantothenate, and to have higher tolerance to ethanol than the Japanese sake yeasts. The biotin requirement was not found in the sake yeasts.

• The Plant Pathology Journal
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• v.16 no.1
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• pp.25-28
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• 2000

The effect of ionic osmotic potential (Ψ$\pi$), and matric potential (Ψm) in the range of -0.2 to -4.0 Mpa on mycelial growth of three species of Pleurotus (P.florida, P.ostrenatus and P.safor-caju) were determined over a range of temperature (15-3$0^{\circ}C$) on a 2% malt extract agar medium and compared with the Ψ$\pi$ effect on growth of two strains of Trichoderma green mould. With the ionic solute KCl, optimun Ψ$\pi$for growth was -0.2 MPa for P.floreda and in the range of -0.2 to -0.5 MPa, with slight growth at -3.0 MPa and with nogrowth at -4.0 MPa. Of the species of Pleurotus, P.florida grew signigicantly slower than the other two species. Growt of the species of Pleurocus was significantly slower when water potential (Ψ$\omega$) was modified matrically with polyethylene glycol (PEG) 8000 then osmotically with KCl. They were also more sensitive to changes in Ψm than Ψ$\pi$The optimum Ψm of the Pleurotus was -0.5 Ψm, with no growth below -3.0 MPa. Of the species of Pleurotus, P.florida was most sensitive and P.sajor-caju was more tolerent to lowered Ψ$\pi$,but P.sajor-caju was most sensitive to lowered Ψm. The growth rate of the Trichoderma green mould strains was much faster than that observed for the Pleurotus spp. Optimum growth for bot strains of Trichoderma was in the range of -0.2 to -0.5 MPa. Strain CNU 503 was more tolerant to water stress than strain CNU 501. Both strains were able to grow up to 30% of optimum growth at -4.0 MPa at 25-3$0^{\circ}C$.

• Journal of Mushroom
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• v.5 no.2
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• pp.81-85
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• 2007

This study was carried out to investigate the conditions of liquid culture and fruiting body formation of Cordyceps militaris using grain mediacontained the brown rice and black purple rice. Liquid mycelial growth and density of Cordyceps militaris were the highest in the medium of malt extract 0.7% and pH 5.0~5.5. The optimal condition of formation the fruiting bodies were shown to be temperature of $17^{\circ}C$, light intensity of 600 lux, $C0_2$ of 500ppm and humidity intensity of 95% produced highest amount of fruit bodies.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.36-41
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• 2007

Phosphate-solubilizing microorganisms were isolated from soil around Kyungnam and Kyungbook regions using potato dextrose agar-calcium phosphate medium. A fungus with the greatest phosphate-solubilizing activity was selected and identified to Aspergillus sp. PS-104, based on the morphological characteristics of conidiophore and conidia; unbranching type of conidiophore, terminally swelling of conidiophore and septate of mycelium, in malt extract agar and potato dextrose agar media. The optimum temperature and initial pH to solubilize rock phosphate in potato dextrose broth-rock phosphate medium were $30^{\circ}C$ and pH 7.0, respectively. In these optimum conditions, phosphate-solubilizing activities of Aspergillus sp. PS-104 against four twos of insoluble phosphate, tricalcium phosphate, aluminium phosphate, hydroxyapatite and rock phosphate, were quantitatively determined. As result, the maximum phosphate-solubilizing activity was obtained with tricalcium-phosphate (1,900 ppm) while minimum activity was obtained with hydroxyapatite (320 ppm). Futhermore, phosphate-solubilizing activity of Aspergillus sp. PS-104 was found higher when treated with nitrates as compared to the ammonium salts as a nitrogen sources.

• The Plant Pathology Journal
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• v.15 no.3
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• pp.152-157
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• 1999

An antibiotic compound was isolated from the culture of an antagonist against Fusarium oxysporum f. sp. sesami, Bacillus polymyxa strain KB-8, and tested for the control of Fusarium wilt of sesame in greenhouse conditions. Optimum conditions for culturing the antagonist to obtain the maximum antibiotic activity were determined using different culture media, initial medium acidity, and incubation periods for which yeast -malt extract agar with the initial acidity of pH 5 and over 13 days culture were best. Antibiotic substances extracted by methanol had 2 main fractions, KB-8A and KB-8B, in thin layer chromatography (OLC) with Rf values of 0.35 and 0.67 in a solvent system of chloroform : methanol = 7 : 3. The fraction KB-8A wa purified further by XAD-2, silica gel and Sephadex LH-20 column chromatography, and crystalization. Its minimum inhibitory concentrations (MICs) were $12.8\mu\textrm{g}$/ml for F. oxysporum and Alternaria mali, $6.4\mu\textrm{g}$/ml for Colletotrichum gloeosporioides and Rhizoctonia solani, and $3.2\mu\textrm{g}$/ml for Phytophthora capsici. Soil drenching of antibiotic KB-8A in the concentrations of $13.0\mu\textrm{g}$/ml and $26.0\mu\textrm{g}$/ml effectively inhibited the Fusarium wilt of sesame in a greenhouse test, which appeared to be comparable to the fungicide benlate of $6.5\mu\textrm{g}$ a. i./ml.

• Mycobiology
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• v.37 no.1
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• pp.28-30
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• 2009

This study was aimed at evaluating the growth promoting effect of symbiotic algal polyol (ribitol) and plant hormones on the lichen-forming fungi (LFF), Ramalina farinacea (CH050010 and 40403) and Ramalina fastigiata. The addition of ribitol to basal (malt-yeast extract) medium enhanced the relative growth rates of all three LFF. R. farinacea (CH050010), R. farinacea (40403) and R. fastigiata (H06127) showed 35.3%, 29.0% and 29.3% higher growth rates, respectively, compared to the control. IBA (indole-3-butyric acid) and TIBA (2,3,5-tridobenzoic acid) also increased growth rates of the LFF by 34 to 64% and 7 to 28%, respectively, compared to the control. The combination of ribitol with IBA or TIBA synergistically increased the growth of all LFF. For example, ribitol and IBA treatments increased growth rates of R. farinacea (CH050010), R. farinacea (40403) and R. fastigiata (H06127) by 79.4%, 40.3% and 72.8% in, respectively, compared to those grown on the basal medium. The stimulating effect of ribitol and IBA on the LFF growth induced vertical development of the fungal mass in culture. We suggest that lichen-forming fungal growth of Ramalina lichens can be stimulated aposymbiotically by supplementing polyols and plant hormones to the basal medium in the mass production of lichen secondary metabolites under large scale culture conditions.