• Mycobiology
• /
• v.51 no.6
• /
• pp.393-400
• /
• 2023

During a disease survey in October 2019, leaf spot symptoms with a yellow halo were observed on Korean angelica (Anglica gigas) plants grown in fields in Pyeongchang, Gangwon Province, Korea. Incidence of diseased leaves of the plants in the investigated fields ranged from 10% to 60%. Morphological and cultural characteristics of two single-spore isolates from the leaf lesions indicated that they belonged to the genus Didymella. Molecular phylogenetic analyses using combined sequences of LSU, ITS, TUB2, and RPB2 regions showed distinct clustering of the isolates from other Didymella species. In addition, the morphological and cultural characteristics of the isolates were somewhat different from those of closely related Didymella spp. Therefore, the novelty of the isolates was proved based on the investigations. Pathogenicity of the novel Didymella species isolates was confirmed on leaves of Korean angelica plants via artificial inoculation. This study reveals that Didymella gigantis sp. nov. causes leaf spot in Korean angelica.

• Mycobiology
• /
• v.51 no.5
• /
• pp.313-319
• /
• 2023

During disease surveys of Angelica acutiloba plants in Korea, leaf spot symptoms were observed in a field in Andong in July 2019, and stem rot symptoms in vinyl greenhouses in Yangpyeong in April 2020. Incidence of leaf spot and stem rot of the plants ranged from 10 to 20% and 5 to 30%, respectively. Morphological and cultural characteristics of fungal isolates from the leaf spot and stem rot symptoms fitted into those of the genus Phoma. Molecular phylogenetic analyses of two single-spore isolates from the symptoms using concatenated sequences of LSU, ITS, TUB2, and RPB2 genes authenticated an independent cluster from other Didymella (anamorph: Phoma) species. Moreover, the isolates showed different morphological and cultural characteristics in comparison to closely related Didymella species. These discoveries confirmed the novelty of the isolates. Pathogenicity of the novel Didymella species isolates was substantiated on leaves and stems of A. acutiloba through artificial inoculation. Thus, this study reveals that Didymella acutilobae sp. nov. causes leaf spot and stem rot in Angelica acutiloba.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.6
• /
• pp.1103-1108
• /
• 2016

Yam anthracnose caused by Colletotrichum gloeosporioides (C.g) is the most devastating disease of yam (Dioscorea sp.). In the present study, we evaluated the culture filtrate extract (CFE) of azalomycin-producing Streptomyces malaysiensis strain MJM1968 for the control of yam anthracnose. MJM1968 showed strong antagonistic activity against C.g in vitro. Furthermore, the MJM1968 CFE was tested for inhibition of spore germination in C.g, where it completely inhibited spore germination at a concentration of 50 μg/ml. To assess the in planta efficacy of the CFE and spores of MJM1968 against C.g, a detached leaf bioassay was conducted, which showed both the treatments suppressed anthracnose development on detached yam leaves. Furthermore, a greenhouse study was conducted to evaluate the CFE from MJM1968 as a fungicide for the control of yam anthracnose. The CFE non-treated plants showed a disease severity of >92% after 90 days of artificial inoculation with C.g, whereas the disease severity of CFE-treated and benomyl-treated yam plants was reduced to 26% and 15%, respectively, after 90 days. Analysis of the yam tubers from the CFE-treated and non-treated groups showed that tubers from the CFE-treated plants were larger than that of non-treated plants, which produced abnormal smaller tubers typical of anthracnose. This study demonstrated the utility of the CFE from S. malaysiensis strain MJM1968 as a biofungicide for the control of yam anthracnose.

• Journal of Advanced Marine Engineering and Technology
• /
• v.34 no.6
• /
• pp.922-934
• /
• 2010

To arrange artificial reefs for marine afforestation effectively, tidal currents were analyzed by numerical experiments, and particle tracking based on tidal currents was carried out to clarify the path of algae spores. The experiments were conducted by the Environmental Fluid Dynamics Code (EFDC), and water column was vertically divided into five layers. Tidal current patterns were showed to be affected by main currents outside of the study area, and two circle currents were observed during the analysis of residual currents. Particle tracking lasted 15 days at three installation places where artificial reefs for marine afforestation could be deployed. According to the results of the particle tracking experiment, particle movements at the No.1 and No. 3 stations were belt types along the coastal line. The No. 2 station documented an ellipse type movement 300~500m from coast line. These results suggest that artificial reefs for marine afforestation should be installed in the belt zones at of the No. 1 and No. 3 stations, and in the ellipse zone at the No. 2 station.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.553-553
• /
• 2012

The artificial shells of hard inorganic nanocomposites on individual cells would protect the cells physically and chemically, and control cell division. These emerging properties could be combined with cell-surface functionalizations for applications to cell-based sensors and assays as well as for fundamental studies on single-cell biology. In this work, individual Chlorella cells were encapsulated within a silica/titania nanocomposite shell in a biocompatible fashion that utilized a designed peptide, RKKRKKRKKRKKDDDDDDDD, as a catalytic template for formation of both $SiO_2$ and $TiO_2$ on the cell surface. The cell viability was maintained, and the division of the encapsulated Chlorella cells was controlled. The cell viability was enhanced compared with the $TiO_2$-shell formation. In addition, the incorporation of $TiO_2$ to the shell made it possible to anchor the ligands of interest to the shell via catechol chemistry. All in all, the combination of biological $SiO_2$ and abiolgical $TiO_2$ for the shell formation gave more tunability of the artificial shells compared with the $SiO_2$ or $TiO_2$ shells only.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.17 no.1
• /
• pp.45-56
• /
• 2015

The distribution of seaweed was examined in Jeonnam archipelago marine ranching area, the coastal of geumo-do, Yosu. Abundance and distribution of seaweed in dropping site of artificial reef were sampled at 6 station at October 2007. Seaweed community were investigated with quadrat method at line-transect by scientific SCUBA divers. as a result, 30 species in total, 4 green, 9 brown and 15 red seaweed were identified. Range of seaweed biomass in all sampling stations were about 1,600~4,000 g/m². At intertidal zone, appearance of individuals and dominance rate were showed higher than below the subtidal line and at depth from 4m to 6m, individuals, dominance rate and biomass were represented low level. characteristic of water in marine ranching area is turbidity and also compensation depth is low. For that reason, individuals of seaweed community were smaller from depth of 4 meters. Therefore, when equip the artificial reef for preparation of seaweed beds need consider that equipment periods(early spring; before releasing marine seaweed spore) and suitable water depth(3~6m).

• Korean journal of applied entomology
• /
• v.16 no.4 s.33
• /
• pp.211-215
• /
• 1977

The Sporulation of Didymella bryomiae were observed under diurnal cycles of light/darkness of near ultraviolet light (NUV) and artificial daylight (ADL) and continous darkness in eight isolates growing on PDA and V-8 juice agar. Light stimulated pycindial and perithecial formation of this fungus on potato dextrose agar and V-8 juice agar. Sprulation was poor in darkness, but some isolates were able to produce pycnidia and perithecia in the absence of light. Perithecial formation was much better under artificial daylight (ADL) on V-8 juice agar than those grown under near ultraviolet light (NUV). In general, cultures grown on V-8 juice agar sporulated better than cultures grown on PDA under three setsof light condition. Most of the pycnidiospores obtained from each isolates of this fungus grown on PDA were non-septate and microtype, but macrotype of non-septate and uniseptate pycnidiospores were produced on V-8 juice agar. Pycnidiospore produced on V-8 juice agar were similar to those produced on the radicle of naturally infected seeds. The appearance of perithecia were quite distinctive from pycnidia. The mature perithecia were darker than pycnidia and whitish spore masses formed on the ostiole of perithecia.

• Microbiology and Biotechnology Letters
• /
• v.41 no.2
• /
• pp.249-252
• /
• 2013

The Bacillus KU801 strain, due to its potential in the field of probiotics for animal use, was isolated from chicken feces. Strain KU801 was identified as Bacillus amyloliquefaciens KU801 based on the results of 16S rRNA sequencing. Vegetative and spore cells of B. amyloliquefaciens KU801 were resistant to artificial gastric juice and artificial bile acid. B. amyloliquefaciens KU801 was found to inhibit the production of nitric oxide (NO) and increase the production of Interleukin-1 alpha (IL-1${\alpha}$). DNA damage induced by N-methyl-Ntion of ninitroso-guanidine (MNNG) was significantly inhibited, in a dose dependent manner, by preincubating MNNG together with B. amyloliquefaciens KU801. These results demonstrate the potential use of B. amyloliquefaciens KU801 as a feed additive.

• The Plant Pathology Journal
• /
• v.26 no.4
• /
• pp.313-320
• /
• 2010

Genetic instability of the rice blast fungus Magnaporthe oryzae has been suggested as a major factor underlying the rapid breakdown of host resistance in the field. However, little information is available on the mechanism of genetic instability. In this study, we assessed the stability of repetitive DNA elements and several key phenotypic traits important for pathogenesis after serially transferring two isolates though rice plants and an artificial medium. Using isolate 70-15, we obtained a total of 176 single-spore isolates from 10 successive rounds of culturing on artificial medium. Another 20 isolates were obtained from germ tubes formed at the basal and apical cells of 10 three-celled conidia. Additionally, 60 isolates were obtained from isolate KJ201 after serial transfers through rice plants and an artificial medium. No apparent differences in phenotypes, including mycelial growth, conidial morphologies, conidiation, conidial germination, appressorium formation, and virulence, or in DNA fingerprints using MGR586, MAGGY, Pot2, LINE, MG-SINE and PWL2 as probes were observed among isolates from the same parent isolate. Southern hybridization and sequence analysis of two avirulence genes, AVR-Pita1 and AVR-Pikm, showed that both genes were also maintained stably during 10 successive generations on medium and plants. However, one reversible loss of restriction fragments was found in the telomere-linked helicase gene (TLH1) family, suggesting some telomere regions may be more unstable than the rest of the genome. Taken together, our results suggest that phenotype and genotype of M. oryzae isolates do not noticeably change, at least up to 10 successive generations on a cultural medium and in host plants.

• Journal of Korean Society of Forest Science
• /
• v.64 no.1
• /
• pp.33-41
• /
• 1984

This study was conducted to examine the physiology of pine mushroom mycelia cultured with various media for artificial culture of pine mushroom. The results obtained were as follows: 1) Among the various media, the medium composed of honey, boiled pine mushroom and soil extract fluid, fibrous root extract fluid, dry yeast, $KH_2PO_4$ inositol, folic acid, and biotin was the best for the growth of pine mushroom mycelium. 2) The optimum temperature for germinating pine mushroom spore and for culturing pine mushroom mycelium, was $24^{\circ}C$ and the optimum pH was 4.5. 3) There was no significant difference in growth between the mycelium separated from the tissue of pine mushroom sporophore and that separated from the spore. 4) No noticeable effect was found on the growth if such salts as $ZnSO_4$, $MnSO_4$, $MgSO_4$, $CaCl_2$ and ferric citrate were added to the Hamada's medium. 5) The addition of fibrous root extract promoted the growth of pine mushroom mycelium. 6) As a carbon source of artificial media, honey was more effective than glucose. 7) The culture infiltration of Mortierlla growing often in Fairy Ring was good for the growth of mycelium compared with the control. 8) The addition of fibrous root extract, inositol, biotin, and folic acid to artificial culture media was greatly effective in growth. When the temperature was lowered $19^{\circ}C$ after mycelium has appeared, the formation of primordium was observed.