• Journal of the Korean Wood Science and Technology
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• v.34 no.2
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• pp.68-77
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• 2006

The heartwood of cengal (Neobalanocarpus heimii) is known to have a high degree of decay resistance by virtue of its high extractive content. After 30 years in ground contact an utility pole of this tropical hardwood was found to be degraded only in the surface layers by cavity-forming soft rot fungi. The present work was undertaken 1) to characterize the degradation of cengal heartwood from the aspect of ultrastructure and chemistry and 2) to investigate the correlation between soft rot decay and its extractive microdistribution in wood tissues. The chemical analysis of cengal heartwood revealed the presence of a high amount of extractives as well as lignin. The wood contained a relatively high amount of condensed lignin and the guaiacyl units. Microscopic observations revealed that vessels, fibers and parenchyma cells (both ray and axial parenchyma) all contained extractives in their lumina, but in variable amounts. The lumina of fibers and most axial parenchyma were completely or almost completely filled with the extractives. TEM micrographs showed that cell walls were also impregnated with extractives and that pit membranes connecting parenchyma cells were well coated and impregnated with extractives. However, fungal hyphae were present in the extractive masses localized in cell lumina, and indications were that the extractives did not completely inhibit fungal growth. The extent of cell wall degradation varied with tissue types. The fibers appeared to be more susceptible to decay than vessels and parenchyma. Middle lamella was the only cell wall region which remained intact in all cell types which were severely degraded. The microscopic observations suggested a close correlation between extractive microdistribution and the pattern and extent of cell wall degradation. In addition to the toxicity to fungi, the physical constraint of the extractive material present in cengal heartwood cells is likely to have a profound effect on the growth and path of invasion of colonizing fungi, thus conferring protection to wood by restricting fungal entry into cell walls. The presence of relatively high amount of condensed lignin is also likely to be a factor in the resistance of cengal heartwood to soft rot decay.

• Journal of Forest and Environmental Science
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• v.32 no.2
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• pp.158-163
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• 2016

Mushroom surveys and collections were conducted in the western and eastern forest areas in Cambodia, and then fungal biodiversity was analyzed by identifying mushrooms. One thousand and three hundreds eighty three specimens were identified by morphological and genetical characteristics, and were classified into 238 species, 160 genera, 52 families, 15 orders, and 3 phylums. The collected mushrooms were immersed in 70% ethyl alcohol for DNA extraction, and the rest of them were dried in the portable mushroom dryer for 12 hrs. Among these mushrooms, the genera Mycena (8.7%), Ganoderma (5.6%), Microporus (5.3%), Marasmius (4.2%), Marasmiellus (3.0%), Phellinus (2.5%), Trametes (2.5%), Hygrocybe (1.9%) and Pycnoporus (1.5%) were dominant. In the western Cambodia, 1,061 specimens were collected from Koh Kong forests, while 263 specimens were collected from the eastern Cambodia, Seima and Mondulkiri forests. Elevations of surveyed sites were ranged from 0 to 750 m above sea level. The number of species observed in the elevation of 251-500 m was the highest as compared to the other ranges of elevation. Daldinia concentrica, Microporus vernicipes, Microporus xanthopus, Pycnoporus coccineus, Stereum hirsutum, and Stereum ostrea were commonly distributed in all ranges of elevation, while the distribution of Ceratomyxa fruticulosa, Panus fulvus, Schizophyllum, Trametes versicolor, and Tyromyces chioneus were limited under 500 m. One hundred and forty one species including Amauroderma sp., Bjerkandera adusta, Trichaptum abietinum, and Tyromyces chioneus were collected only in Cardamom, while 20 species including Auricularia auricula-judae, Coriolopsis sanguinaria, Rigidoporus microporus, and Xylaria polymorpha were collected only in Seima. Ganoderma sp., Mycena sp., Marasmius sp., Microporus xanthopus, Phellinus sp., and Russula sp. were dominant species in both the western and eastern Cambodia. Species diversity indices in the eastern and western survey sites were 1.83 and 1.77, respectively, while evenness indices were 0.92 and 0.90. The species similarity index between two survey sites was 0.42.

• The Korean Journal of Mycology
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• v.19 no.2
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• pp.109-119
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• 1991

The vertical distribution of the fungal population for the soil samples from two sites of producing and nonproducing of Tricholoma matsutake, song-yi mushroom, were examined at Yang­yang and Myung-joo, Gangweon province. By the dilution plate method, a total number of propagu­les of fungi per gram of soil was observed to be low at the song-yi producing sites but high at the song-yi nonproducing sites under the communities of Pinus densiflora. The tendency of the number of fungal propagules were decreased with the increasing vertical depth. In the incuhation method at $42^{\circ}C$, six genera and nineteen species of the fungi were isolated from two sites; Aspergillus fumigatus, Acremonium sp., Talaromyces stipitatus, Penicillium lilacinum, P. oxalicum and Westerdykella multispora. The most dominant species by this method was A. fumigatus. From heat treatment method at $70^{\circ}C$, seven genera and nineteen species were isolated; Aspergillus fumigatus, Alternaria alternata, Neurospora sitophila and Mucor sp.. In the ethanol treatment method, one genera and one species was isolated Mortierella sp.. From the three isolation methods, it was found that the total number of the soil fungi and the frequency of species appeared were the highest at the soil of upper layer whereas the lowest at the soils of lower layer in its vertical distribution.

• The Korean Journal of Mycology
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• v.46 no.2
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• pp.122-133
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• 2018

The Seonamsa temple is located on steep terrain surrounded by forests and valleys, and is a place that the temple is scared of biological damage because it has high humidity and low wind levels. Therefore, we investigated a concentration and diversity of airborne fungi in indoor and outdoor by collecting air each season. The outdoor fungal load was far higher in spring ($276CFU/m^3$), autumn ($196CFU/m^3$), summer ($128CFU/m^3$) than in winter ($24CFU/m^3$). The lowest located Jijangjeon and upper located Wontongjeon showed the highest distribution of $337.4CFU/m^3$ in summer and $333.4CFU/m^3$ in autumn, respectively. Summer is the season with large variations in the concentration of airborne fungi between indoor and outdoor, a concentration of airborne fungi in indoor was maximum three times higher than these in outdoor with $128CFU/m^3$. Although the most fungi were collected in spring, fungal diversity was richer in summer and autumn with 28 genera 45 species and 25 genera 47 species, respectively. In particular, the concentration of airborne fungi was the most highest in all sampling sites in autumn, of which Ascomycota members accounted for 86% and Cladosporium genus was dominated. The most kind of Penicillium (16 species) was mainly distributed in indoor air in summer, autumn and winter.

• Journal of odor and indoor environment
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• v.17 no.4
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• pp.355-361
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• 2018

Mold grows more easily when humidity is higher in indoor spaces, and as such is found more often on wetted areas in housing such as walls, toilets, kitchens, and poorly managed spaces. However, there have been few studies that have specifically assessed the level of mold in the indoor spaces of water-damaged housing in the Republic of Korea. We investigated the levels of airborne mold according to the characteristics of water damage types and explored the correlation between the distribution of mold genera and the characteristics of households. Samplings were performed from January 2016 to June 2018 in 97 housing units with water leakage or condensation, or a history of flooding, and in 61 general housing units in the metropolitan and Busan area, respectively. Airborne mold was collected on MEA (Malt extract agar) at flow rate of 100 L/min for 1 min. After collection, the samples were incubated at $25^{\circ}C$ for 120 hours. The cultured samples were counted and corrected using a positive hole conversion table. The samples were then analyzed by single colony culture, DNA extraction, gene amplification, and sequencing. By type of housing, concentrations of airborne mold were highest in flooded housing, followed by water-leaked or highly condensed housings, and then general housing. In more than 50% of water-damaged housing, the level of airborne mold exceeded the guideline of Korea's Ministry of Environment ($500CFU/m^3$). Of particular concern was the fact that the I/O ratio of water-damaged housing was greater than 1, which could indicate that mold damage may occur indoors. The distribution patterns of the fungal species were as follows: Penicillium spp., Cladosporium spp. (14%), Aspergillus spp. (13%) and Alternaria spp. (3%), but significant differences of their levels in indoor spaces were not found. Our findings indicate that high levels of mold damage were found in housing with water damage, and Aspergillus flavus and Penicillium brevicompactum were more dominant in housing with high water activity. Comprehensive management of flooded or water-damaged housing is necessary to reduce fungal exposure.

• The Plant Pathology Journal
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• v.31 no.3
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• pp.203-211
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• 2015

Maize is the dominant cereal crop produced in the US. One of the main fungal pathogens of maize is Fusarium verticillioides, the causative agent of ear and stalk rots. Significantly, the fungus produces a group of mycotoxins - fumonisins - on infested kernels, which have been linked to various illnesses in humans and animals. Nonetheless, durable resistance against F. verticillioides in maize is not currently available. In Texas, over 2.1 million acres of maize are vulnerable to fumonisin contamination, but understanding of the distribution of toxigenic F. verticillioides in maize-producing areas is currently lacking. Our goal was to investigate the genetic variability of F. verticillioides in Texas with an emphasis on fumonisin trait and geographical distribution. A total of 164 F. verticillioides cultures were isolated from 65 maize-producing counties. DNA from each isolate was extracted and analyzed by PCR for the presence of FUM1- a key fumonisin biosynthesis gene - and mating type genes. Results showed that all isolates are in fact F. verticillioides capable of producing fumonisins with a 1:1 mating-type gene ratio in the population. To further study the genetic diversity of the population, isolates were analyzed using RAPD fingerprinting. Polymorphic markers were identified and the analysis showed no clear correlation between the RAPD profile of the isolates and their corresponding geographical origin. Our data suggest the toxigenic F. verticillioides population in Texas is widely distributed wherever maize is grown. We also hypothesize that the population is fluid, with active movement and genetic recombination occurring in the field.

• Journal of Ecology and Environment
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• v.39 no.1
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• pp.91-97
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• 2016

This paper reports the species of macromycetes collected in Mongolia: all the species are new to the area. Brief notes on taxonomy, ecology and distribution of the species are added. A total of 30 species of macromycetes were registered, 1 belonging to the division Ascomycota and 29 to the division Basidiomycota. It has been registered that 30 species belong to 25 genera, 17 families and occur in the flora fungus of Mongolia, until now. Specimen for 150 of samples macromycetes collected from June to August, 2015 in Tuv, Arkhangai and Huvsgul were enveloped. Macromycetes have been occured in 9 of 16 geographic regions. According to our studies 2 species in Khubsgul region, 2 species in Khangai region, 3 species in Khingan, 3 species in Dornod Mongol, 1 species in Khentei regions newly registered respectively. As a result of this work, determined 7 species (23%) of macromycetes in forest steppe and steppe regions and 23 species (77%) of them in forest region. The trophic structure for the fungal species is as follows: 2 species lignophite (7%), 4 species moss saprophyte (13%), 5 species soil saprophyte (17%), 15 species mycorrhiz (50%) of all species were respectively.

• Korean Journal of Organic Agriculture
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• v.31 no.1
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• pp.95-106
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• 2023

Entomopathogenic fungi are one of the microorganisms distributed worldwide, and they inhabit not only insects but also soils of various regions such as agricultural land and forest areas. In this study, entomopathogenic fungi distributed in the soil of forest areas in Korea were isolated using the insect-baiting method, and the relationship between the distribution and diversity of entomopathogenic fungi and the physical/chemical characteristics of the soil was analyzed. The soils were collected from five forest areas in Korea, and a total of 42 entomopathogenic fungal isolates were isolated from the collected soils. Among them, Beauveria bassiana (42.9%) and Metarhizium anisopliae (45.2%) were mainly isolated. In particular, it was confirmed that the distribution of M. anisopliae varies depending on the total nitrogen (g/kg) and organic matter content (%) of the soil. The soils in forest areas in Korea have a low pH of 4-5. Among all isolates, >50% of entomopathogenic fungi were isolated from silt loam. This study suggests that it will be helpful in understanding the relationship between the distribution and diversity of entomopathogenic fungi and the physical and chemical characteristics of soil.

• Korean Journal of Medicinal Crop Science
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• v.28 no.2
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• pp.152-166
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• 2020

Background: Ginsenosides, which have various physiological activities, are known to be abundant in the leaves and roots of ginseng. Ginseng sprouts can be used as a fresh vegetable and roots, stems, and leaves of ginseng can be consumed. This study aimed to investigate the effect of carbon dioxide treatment and the modified atmosphere (MA) packaging method in suppressing quality deterioration during the distribution of ginseng sprouts. Methods and Results: Ginseng sprouts were packed using Styrofoam, barrier film + non gas treatment, barrier film + gas treatment, 15 ㎛ polyamide (PA) double film + non gas treatment, 15 ㎛ PA double film + gas treatment, 25 ㎛ PA film + non gas treatment, or 25 ㎛ PA film + gas treatment. Quality parameters including gas composition, relative humidity, chlorophyll SPAD (Soil Plant Analysis Development) value, firmness, and rate of quality loss in ginseng sprouts were monitored at the following temperatures: 20℃, and 10℃. Ginseng sprouts packaged with 25 ㎛ PA film showed loss in quality because of wilting owing to low relative humidity within the film. Chlorophyll and firmness did not differ between film and gas treatments. The time point at which the combined loss from softening and decay owing to fungal, and bacterial infection and wilt reached 20% was considered the limit of distribution. At 20℃, the packaging not included in the 20% distribution loss rate limit or up to 7 days was 15 ㎛ PA double film + gas treatment. At 10℃, the packaging not included in the 20% distribution loss rate limit for up to 18 days were barrier film + gas treatment and 15 ㎛ PA double film + gas treatment. Conclusions: The film packaging suitable for the distribution of ginseng sprouts was found to be the barrier film and PA film with low gas permeability and maintaining hygroscopicity at 95% relative humidity. To prevent the loss in quality of ginseng sprouts, gas treatment (8% of O₂ and 18% of CO₂) in the film was found to be more suitable than no gas treatment for inhibition of decay.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.123.2-124
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• 2003

Fusarium graminearum (telomorph：Gibberella zeae), an important fungal pathogen of cereal crops with ubiquitous geographic distribution, produces mycotoxins on diseased crops that has threaten human and animal health. Recently severe epidemics of scab diseases of barley and rice by this fungus occurred in Korea, causing serious economic losses. To determine genetic diversity of F. graminearum from rice in Korea, a total of 269 isolates were obtained from Southern part of Korea during 2001-2002. A phylogenetic tree of the isolates was constructed by using amplified fragment length polymorphism (AFLP). Population structure of the rice isolates consists of a single lineage (lineage 6). Frequency of female fertility among these Isolates was relatively low (37％) compared to that among lineage 7 isolates from Korean corn. PCR amplification using chemotype specific primers derived from Tri7 and Tri13 genes at the trichothecene biosynthesis gene cluster revealed that most isolates (260) were NIV chemotype；9 isolates were identified as DON chemotype by Tri13 but as either NIV chemotype or unknown by Tri7. The result of chemical analysis also supported the chemotype determination；all of the NIV chemotype isolates produced NIV, whereas the 9 isolates produce either DON or no toxin.