• 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.

• The Korean Journal of Mycology
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• v.32 no.1
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• pp.39-44
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• 2004

Gastrodia elata has been cultivated using mycorrizal fungi including Armillaria mellea as an energy source (myco-hetrotrophy) because it is aphyllous and achlorophyllous archid. But the yields of G. elata have been recently decreased owing to the degeneration of spawn tuber arised from successive asexual reproduction. Therefore, this study was carried out to solve this degeneration by seed germination, namely sexual reproduction. The seed germination of G. elata was excellent on the fallen leaves medium of oak tree. The fruetification rate of the capsule of G. elata by artificial pollination was 94.1% and better than natural pollination. The living weight of capsules of G. elata suitable for seeds germination was above 31 mg. The middle-matured seeds and matured seeds of capules were largely germinated, while the immatured seeds was small germinated. The storage temperature of the cropped capsules suitable for a favorable seed germination was $0{\sim}5^{\circ}C$ and the storage period of it was one month.

• The Korean Journal of Mycology
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• v.39 no.1
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• pp.16-21
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• 2011

Ginseng root rot caused by Cylindrocarpon destructans is one of the most destructive diseases of ginseng(Panax ginseng). We analyzed the features of the species through pathogenicity test and genetic diversity analysis of C. destructans in Korea, for its application as basic data to attempt for effective control. C. destructans isolated from rotted ginseng roots exhibited a variety of colonial colors on media. It was assumed that there may exist genetic diversity in the population by the diversity of pathogenicity among isolates observed when artificially inoculated into ginseng roots. Pathogenicity tests using ex vivo wound inoculation with agar mixture inoculation on ginseng roots were performed similar results as were observed appear to be useful for rapid pathogen inspection. According to RAPD analysis results, Korean C. destructans isolates formed a single genetic group which can be distinguished readily from closely related other fungi. C. destructans group was divided into two small groups. Therefore, we were able to confirm pathogenicity and genetic difference between the isolates in each of the groups of the pathogen.

• Journal of fish pathology
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• v.6 no.1
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• pp.1-10
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• 1993

Two vibrio sp. strains were isolated from disease catfish(silurus asotus). The present isolates were identified as Vibrio ordalii based on their biological and biochemical characteristics ; they were positive for acid production from glucose, Iactose, maltose, sucrose and salicine, while negative for arabinose, galactose, inocitol and xylose. They are named KL-1 and KL-2, KL-1 and KL-2 strains were similar to physiological characteristics ; growth was observed at pH 5 to 10 and in 0% to 6.0% NaCl. Two strains did not growth at a concentration above 7.0% NaCl and pH10. This bacterium was infected into health catfish hypodermically. Such injection was found to induce haemorrhagic ulcers very similar to those observed in naturally infected fish. At 24h post-infection, the red spot developed around the injection site and grew bigger to from a red sport area. At 120h post-infection, the muscle ncerosis was extended near the ventral fin. The seventy percent lethal dosage was appeared to water temperature at $25^{\circ}C$. Two strains were tested for drug senistiveity by plate method. KL-1 and KL-2 strains were sensitive to GM. K, N, S and SxT, but resistant to CF, L and VA.

• Journal of Plant Biotechnology
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• v.31 no.1
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• pp.31-35
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• 2004

In order to develop an efficient micropropagation technique for an endangered species, Stellera rosea N., stem node cultures were conducted on MS medium supplemented with cytokinins. Generally, BA was better than zeatin on shoot proliferation from stem nodes, whereas zeatin showed more effective on shoot elongation. In vitro rooting of shoots was achieved by application of an auxin pre-culturing method. Overall rooting rate was relatively low and differed depending on the culture period. Pre-culturing of shoots for 15 days at 1.0mg/L IBA revealed a slightly better rooting efficiency reaching 30％ rooting rate than NAA. Root induction rate by NAA also varied with concentration of NAA and culture periods. Total 51％ of the rooted plantlets survived on artificial soil mixture and grew normally without any distinct morphological variation. The results suggest that the endangered Stetllera plants are propagated via in vitro culture system, but still need to more study for the improvement of rooting and acclimatization of the plantlets in soil.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.3
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• pp.129-137
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• 1989

Sand fish, Arctoscopus japonicus (Steindachner) is distributed in the coastal waters of East Sea of Korea, Japan, and Alaska. On December 1, 1987, matured adult of sand fish were collected from the shore of Ok-kye, Myongju-gun, Kangwon-do, Korea. The authors carried out artificial insemination on boat. The fertilized eggs were incubated and the larvae were reared in laborato교. The eggs of this species were demersal and adhesive, and their diameter were varied within $3.1\~3.4$mm (mean 3.3 mm, n= 10). They have a number of small oil globules. The spawned eggs in nature were formed the egg mass which were measured ca. 4 m in dia-meter. The hatching took place in 65 days after fertilization at the water temperature of $8.7\~12.3^{\circ}C$. The newly hatched larvae were $8.5\~10.2$ mm in total length with 11 (abdominal) +40 (caudal) = 51 myomeres. 24 days after hatching, the larva attained 19.4 mm in total length, at this time the larvae absorbed the yolk completely, and become postlarvae. 32 days after hatching, the larva attained 23.4 mm in total length, and become juvenile. 56 days after hatching, the juvenile reached 29.9 mm in total length and had adult form. 5 spines of preopercle bone were formed at 24.4 mm in total length. At ca. 15 mm in total length, the form of the pectoral fin was transformed into the adult form.

• Journal of Life Science
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• v.30 no.10
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• pp.919-929
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• 2020

Aromatic compounds are widely used in the chemical, food, polymer, cosmetic, and pharmaceutical industries and are produced by mainly chemical synthesis using benzene, toluene, and xylene or by plant extraction methods. Due to many rising threats, including the depletion of fossil fuels, global warming, the strengthening of international environmental regulations, and the excessive harvesting of plant resources, the microbial production of aromatic compounds using renewable biomass is regarded as a promising alternative. By integrating metabolic engineering with synthetic and systems biology, artificial biosynthetic pathways have been reconstituted from L-tryptophan biosynthetic pathway in relevant microorganisms, such as Escherichia coli and Corynebacterium glutamicum, enabling the production of a variety of value-added aromatic compounds, such as 5-hydroxytryptophan, serotonin, melatonin, 7-chloro-L-tryptophan, 7-bromo-L-tryptophan, indigo, indirubin, indole-3-acetic acid, violacein, and dexoyviolacein. In this review, we summarize the characteristics, usage, and biosynthetic pathways of these aromatic compounds and highlight the latest metabolic engineering strategies for the microbial production of aromatic compounds and suitable solution strategies to overcome problems in increasing production titers. It is expected that strain development based on systems metabolic engineering and the optimization of media and bioprocesses using renewable biomass will enable the development of commercially viable technologies for the microbial production of many aromatic compounds.

• Research in Plant Disease
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• v.17 no.2
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• pp.184-190
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• 2011

Ralstonia solanacearum, a causal agent of bacterium wilt is very difficult to control once the disease becomes endemic. Thus, Ralstonia solanacearum is a plant quarantine bacterium in many countries including Korea. In this study, we developed PCR assays, which can detect Ralstonia solanacearum from the Solanaceae seeds. Primers RS-JH-F and RS-JH-R amplified specifically a 401 bp fragment only from Ralstonia solanacearum race 1 and race 3. The nested PCR primers, RS-JH-F-ne and RS-JH-R-ne that were designed inside of 1st PCR amplicon amplified specifically a 131 bp fragment only from Ralstonia solanacearum race 1 and race 3. The primers did not amplify any non-specific DNA from the seed extracts of the Solanaceae including tomato and pepper. When detection sensitivity were compared using the Solanaceae seeds inoculated with target bacteria artificially, the nested PCR method developed in this study 100 times more sensitive than ELISA and selective medium. Therefore, we believe that the PCR assays developed in this work is very useful to detect Ralstonia solanacearum in the Solanaceae seeds.

• Journal of dental hygiene science
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• v.15 no.4
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• pp.437-444
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• 2015

Due to the attractive benefits with regard to bone health, digestion, and hydration, carbonated water consumption have rapidly grown over the past few years. However, the acidic drink has latent potential for enamel erosion. The most experimental studies about the enamel erosion have focused on the carbonated beverages with sugar and artificial sweeteners. Here, we determined the enamel erosion potential by commercially available carbonated waters with bovine teeth. The erosion was verified by pH value, calcium concentration, and scanning electron microscope. Then plaque accumulation by bacterial adhesion was determined on the enamel erosion surface to measure roughness. In the present study, we observed that the increased calcium content after being immersed in carbonated waters result from the overall enamel erosion. There were no significant differences between general carbonated waters and mineral waters for erosive capacity. Therefore, commercially available carbonated waters are potentially erosive. In addition, oral bacteria strongly adhered to the erosive enamel surfaces thereby facilitating the development of dental plaque. Thus, it is urgently necessary to provide food safety information on the carbonated water as acidic drink to prevent the enamel erosion.

• Research in Plant Disease
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• v.16 no.1
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• pp.48-58
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• 2010

In Korea, EBI fungicides which are highly effective for control of pear scab and rust but of high risk for development of resistance have been frequently sprayed by majority of pear growers. To detect any possible resistance or reduced sensitivity in the field strains of scab fungus to five EBIs, difenoconazole, fluquinconazole, flusilazole, fenarimole and hexaconazole, sensitivity tests were conducted with fungal specimens collected in Ulsan and Naju where scab usually occurs and EBIs have been intensively sprayed for many years. As the strains for which $EC_{50}$ values of the EBIs were largely shifted from those of base-line were occasionally found, the resistant or less sensitive strains were supposed to be distributed. In the activity test for the EBIs by artificial inoculation, in which EBI-treated pear leaves on the potted seedlings were inoculated with fungal spores collected in the two regions, development of resistances to EBIs were confirmed. Since the fungal spores collected at 4 and 2 orchards in Naju and Ulsan, respectively, produced much higher disease incidence on the leaves treated with hexaconazole than those on the untreated control, those fungal specimens were determined as resistant to hexaconazole. Similar results were also obtained with two specimens from Ulsan for flusilazole.