• The Korean Journal of Mycology
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• v.43 no.3
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• pp.137-141
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• 2015

This study focused on isolation of wild yeasts from natural flowers and elucidation of yeast diversity. Wild yeasts were isolated from various flowers collected from mountains on the islands including Jejudo, Ulleungdo, Yokjido, and Seonyudo as well as inlands including Gyejoksan, Oseosan, Beakamsan, and Deogyusan in Korea. Isolated yeasts were identified by comparison of nucleotide sequences for polymerrase chain reaction-amplified D1/D2 region of 26S rDNA or internal transcribed spacer 1 and 2 including 5.8S rDNA using BLAST. 289 strains belonging to 134 yeast species were isolated. Cryptococcus genus strains were the most frequently isolated species among the identified yeasts. Metschnikowia reukaufii was also frequently isolated. Twenty three species including Cryptococcus aureus were overlapped between those of mountains on islands and inland. Physiological functionalities such as antioxidant activity, xanthine oxidase inhibitory activity, and tyrosinase inhibitory activity for the 289 identified yeast strains were investigated using their supernatant and cell-free extracts. The supernatants of Candida sp. 78-J-2 and Metschnikowia reukaufii SY44-6 showed antioxidant activity of 22.5%, and anti-gout xanthine oxidase inhibitory activity of 49.6%, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.2
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• pp.155-160
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• 2008

In this study, the nitrate removal efficiency was examined under a variety of operating conditions, such as different doses of the reducing agent, different electrode types, different HRTs(hydraulic retention times), and different current densities, using the multistep electrochemical process. The nitrate removal efficiency increased and the input energy decreased when the reducing agent was used, and almost no difference was found between the electrode types in terms of their nitrate removal efficiency and current efficiency. So that the Zn reducing agent could be recovered, though, the B-type electrode was chosen(step 1: Pt-Zn; step 2: Pt-Zn; step 3: Pt-Zn; step 4: Pt-Zn). HRT experiments were carried out on constant electric current density unrelated HRTs and various electric current density related HRTs: the constant amount of electric current per unit volume. As a result, HRT and the electric current density caused concentration polarization and the lack of an applied current. That is to say,the lower the HRT, the greater the decrease in concentration polarization and in the amount of applied current per unit volume. Therefore, optimal conditions were found through the experiments that were conducted on HRT and electric current density. When a spacer was installed in the process, the nitrate removal efficiency and energy efficiency increased even more because the diffusion likewise increased.

• Journal of Mushroom
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• v.2 no.4
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• pp.169-174
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• 2004

A hot water extract(HWE-P4) was separated from the fruit bodies of PMO-P4, and its antitumor and immunomodulatory activities against sarcoma-180 in ICR mice were investigated. The internal transcribed spacer(ITS) regions from PMO-P4 were amplified using polymerase chain reaction(PCR) and sequenced. The results revealed that PMO-P4 was belong to the Phellinus baumii. When oral administration at the dose of 160mg/kg/day in the mice until the end of the experiment with 2 week's pre-feeding of the HWE-P4, the survival rate of the mice was 152% for 50days after the inoculation of sarcoma-180 and the suppression rate of the tumor growth was 35.3%(p<0.05) for 28 days after inoculation of sarcoma-180. The HWE-P4 increased 71.4% of the CD4/CD8 ratio and 5-fold of the expression of CD25(IL-2 receptor chain) compared with the control. From these results, the antitumor activity of HWE-P4 is exerted through its immunomodulating activity on the host's immune system.

• Journal of Mushroom
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• v.10 no.3
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• pp.143-149
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• 2012

Armillaria spp are well known as a symbiotic fungus with Gastrodia elata. This study was carried out to identify and analyze the genetic relationships among 83 strains of Armillaria spp.. The amplified internal transcribed spacer(ITS) region of the rDNA was about 500~750 bp long and identified by 9 strains; A. mellea, A. tabescens, A. ostoyae, A. gallica, A. novae-zenlandia, A. cepistipes, A. nabsnona, A. gemina, A. sinapina. Sequence analysis showed that 52% of strains were different with original identification. A. gallica, A. cepistipes and A. gemina were so close phylogenetic relationship, that was difficult to classify using ITS region. In A. gallica, 12 strains including ASI10104 were showed a close phylogenetic relationship with A. gallica, A. cepistipes and A. gemina. ASI10017 and ASI10114 were classified as the A. sinapina group, ASI10045 was the A. borealis group, ASI10002 and ASI10025 were the A. ostoyae group. So more studies need for more accurate identification and determine the phylogenetic relationships of Armillaria spp.

• Journal of Life Science
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• v.12 no.6
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• pp.821-834
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• 2002

In order to measure the inter- and intraspecific genetic divergences within the genus Alexandrium, the variations within the internal transcribed spacer (ITS1 and ITS2) regions and 5.85 ribosomal RNA gene of eight Alexandrium species were examined for 33 strains from diverse geographical locations by direct sequencing. Five isolates of A. tamarense (AT-2, AT-6, AT-10, AT-A and AT-B) from Jinhae Bay, Korea were found to be completely identical to a Japanese strain OFX151-A. The length of the amplified ITSI-5.85-ITS2 region varied from 481 nucleotides (in A. margalefi) to 528 nucleotides (in A. affine CU1-1). ITS1 and ITS2 nucleotide lengths were negatively correlated, whereas a positive correlation was found between their G＋C content. The degree of sequence divergence ranged from 0.3% (1 bp) to a maximum of 53% (305 Up). Pairwise sequence comparisons revealed a small degree of divergence between A. tamarense and A. Pundyense isolates (1.2 - 2.3% ＝ 6-12 bp), but a high degree of divergence between A. tamarense and A. catenella (19.8% ＝ 102 bp), and between A. catenella and A. Pundyense (19.7%). Although most nodes were weakly supported by bootstrap values, some types tend to form independent molecular groups. A. catenella isolates also formed an independent molecular sub-group, with relaticula strong bootstrap values (94% or 85% and 79% or 98%, respectively in PAUP and NJ trees). Interestingly, A. cohorticula and A. frateculus always clustered within the same sub-group, this result being supported by strong bootstrap values. Our results indicate that the ITS regions provide useful informations on hierarchical population genetic structure and a high phylogenetic resolution in intraspecific and interspecific Alexandrium population.

• Journal of Life Science
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• v.24 no.11
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• pp.1174-1179
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• 2014

This research was carried out to evaluate whether gamma ray is a useful tool for breeding new strains of mushrooms. For this research, 5 mutant groups, 20 strains of Hypsizigus marmoreus, 2 strains of Lyophyllum decastes, and 1 strain of Lyophyllum shimeji were used. Monokaryon spores from one variety of H. marmoreus were irradiated with 50~2,000 Gy of gamma ray. The propriety dose was 50~200 Gy for mutagenesis. Mutant monokaryon mycelia crossed each order to become dikaryon mycelia. The internal transcribed spacer (ITS) regions of rDNA were amplified using PCR, and the products were sequenced. The sequences of the ITS regions (16 partial rDNA, complete ITS1, 5.8 rDNA and partial rDNA) were analyzed by PCR, and strains of H. marmoreus, L. decastes, and L. shimeji were auto-sequenced. The lengths of the sequenced ITSs were 1,052~1,143 nucleotides. Genetic matrices were calculated using Nei-Li's genetic distance coefficient based on ITS sequence. The dissimilarities were 0~3.35% in strains of H. Hypsizigus. In addition, a phylogenetic tree was constructed based on ITS sequences using the neighbor-joining (NJ) method. The phylogenetic tree revealed that 23 strains and 5 mutant groups were divided into 12 clusters; the mutant groups fell into different clusters. These results show that mushroom spores were mutated effectively by gamma ray; therefore, gamma ray could be a useful tool for breeding new strains of mushrooms.

• Research in Plant Disease
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• v.22 no.2
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• pp.122-126
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• 2016

In June 2015, an exhibited typical signs and symptoms of brown rot was observed on fruit of Apricot cvs. Modern and Alexander at an incidence of 5% of fruit in Jeonju, Korea. Early symptoms on fruit showed small, circular, light brown spots that eventually destroyed the entire fruit. Small sporodochia appeared on the fruit surface. Fruit susceptibility to brown rot increases during the 1 to 2 weeks period prior to harvest. The conidia were one-celled, hyaline, lemon-shaped, $14.6-18.0{\times}8.5-11{\mu}m$, and borne in branched monilioid chains. Based on the morphological characteristics and phylogenetic analysis of internal transcribed spacer (ITS), the fungus was identified as Monilinia fructicola. A BLAST search revealed that sequences of the fungus shared 100% identity to those of M. fructicola. Pathogenicity of a representative isolate was proved by artificial inoculation, fulfilling Koch's postulates. To our knowledge, this is the first confirmed report on the occurrence of M. fructicola on apricot in Korea.

• Research in Plant Disease
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• v.25 no.4
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• pp.220-225
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• 2019

During the year 2018, the symptoms of bunch rot on Shine Muscat (Vitis vinifera L.) were observed in Kimcheon-si, Gyeongbuk province in Korea. The disease appears on the Shine Muscat as a black rot due to prolific fungal sporulation after it has invaded into the Shine Muscat which look completely empty and dryness. Colonies of these fungi are present on the Shine Muscat skin from fruit setting and increase in amount from early season to harvest, while become peak at ripening stage. To isolate the causal agent, small fragments (2 to 3 mm) of decayed tissue from the lesion margin were placed onto potato dextrose agar (PDA) plates. Fungal colonies on PDA produced dense white aerial mycelium and then covered with dark black conidial heads. These heads were large and radiate, and vesicles were globose (2.12-32.0×2.0-3.1 ㎛). Based on morphological and cultural characteristics, this fungus was identified as Aspergillus tubingensis. To confirm its identity, the internal transcribed spacer, β-tubulin, and RNA polymerase II was sequenced for molecular identification. BLAST search indicated 99% identity with A. tubingensis. The pathogenicity test on healthy grape of Shine Muscat produced bunch rot, as the original symptoms. To select effective fungicides for the control of brunch rot, an in vitro antifungal activity of seven fungicides were evaluated against the growth of A. tubingensis. Five fungicides (dipenoconazole, tebuconazole, metconazole, iminoctadine, and captan) exhibited significantly strong suppression of the mycelial growth of A. tubingensis.

• Research in Plant Disease
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• v.23 no.4
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• pp.322-333
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• 2017

In June and July 2015 and 2017, typical signs and symptoms of brown rot were observed on the fruit of Japanese apricot, peach, apricot, Japanese plum, and sweet cherry with incidence levels of 2-5% in Jeonju and Imsil, Korea. Early symptoms were small, circular, light brown spots that eventually destroyed entire fruit. Small sporodochia later appeared on the surface. Conidia isolated from each host were one-celled, hyaline, lemon-shaped and borne in branched monilioid chains. The optimal temperature range for hyphal growth of all the isolates was $20-25^{\circ}C$. The growth of hyphae was faster on potato dextrose agar and oatmeal agar than others. Multiple alignments using the ITS sequences from different host showed that they matched each other (100%). The ITS sequences showed 100% identity to those of M. fructicola. Based on the morphological characteristics and phylogenetic analysis via internal transcribed spacer (ITS), all the isolate was identified as M. fructicola. Pathogenicity of representative isolates was proved by artificial inoculation, fulfilling Koch's postulates. This is the first confirmed report on brown rot caused by M. fructicola on stone fruit in Korea.

• Parasites, Hosts and Diseases
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• v.56 no.5
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• pp.419-427
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• 2018

This study aimed to develop a new multiplex real-time PCR detection method for 3 species of waterborne protozoan parasites (Cryptosporidium parvum, Giardia lamblia, and Cyclospora cayetanensis) identified as major causes of traveler's diarrhea. Three target genes were specifically and simultaneously detected by the TaqMan probe method for multiple parasitic infection cases, including Cryptosporidium oocyst wall protein for C. parvum, glutamate dehydrogenase for G. lamblia, and internal transcribed spacer 1 for C. cayetanensis. Gene product 21 for bacteriophage T4 was used as an internal control DNA target for monitoring human stool DNA amplification. TaqMan probes were prepared using 4 fluorescent dyes, $FAM^{TM}$, $HEX^{TM}$, $Cy5^{TM}$, and CAL Fluor $Red^{(R)}$ 610 on C. parvum, G. lamblia, C. cayetanensis, and bacteriophage T4, respectively. We developed a novel primer-probe set for each parasite, a primer-probe cocktail (a mixture of primers and probes for the parasites and the internal control) for multiplex real-time PCR analysis, and a protocol for this detection method. Multiplex real-time PCR with the primer-probe cocktail successfully and specifically detected the target genes of C. parvum, G. lamblia, and C. cayetanensis in the mixed spiked human stool sample. The limit of detection for our assay was $2{\times}10$ copies for C. parvum and for C. cayetanensis, while it was $2{\times}10^3$ copies for G. lamblia. We propose that the multiplex real-time PCR detection method developed here is a useful method for simultaneously diagnosing the most common causative protozoa in traveler's diarrhea.