• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.531-538
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• 2009

Xylitol has the ability to reduce the adherence of Streptococcus mutans(S. mutans), which can make it easier to remove plaque, decrease acid production and inhibit dental caries. There are few reports on the effects of xylitol on the expression of the virulence related genes in S. mutans. This study examined the inhibitory effect of chewing gum containing xylitol on glucan synthesis related gene expression of S. mutans. Participants were voluntarily recruited for a women's oral health prevention program, classified into two groups(a control and a xylitol group), and then followed for 2 years. Twenty salivary samples were randomly selected from each group. Colony count and real-time reverse transcription polymerase chain reaction were used to analyze the characteristics of S. mutans. The following results were obtained: The S. mutans counts decreased steadily in the xylitol group over the study period(p<0.05). The expression of the virulence related genes (gtfB, gtfC and gtfD) was significantly lower in the xylitol group than in the control groups (p<0.05). In conclusion, these results suggest that chewing xylitol gum for a long period of time may reduce the expression of the genes associated with S. mutans virulence, which can result in a decrease growth of S. mutans colonies as a result.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.58-64
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• 2007

Overwintering adults of sycamore lace bug (Corythucha ciliata) infected by an unidentified pathogenic fungus were found on the stems of street trees of sycamore in Cheongju city. The objective of this study was to describe this entomopathogenic fungus infecting overwintering sycamore lace bug adults. This unidentified fungus colonized the insect adult body and formed white colony with subglobose clusters of conidiocarps. The size of conidiocarps was 300 to $400{\mu}m$ and each conidium was 15 to $20{\mu}m$. The conidiospore was globus and 2.5 to $3.0{\mu}m$ in diameter, and the hyphae were 1 to $5{\mu}m$ thick. This fungus was successfully isolated and cultivated on potato dextrose agar medium (PDA). The fungal colony was white and then became light yellow. When conidia from this pure culture were inoculated into the overwintering adults, the fungus formed conidiocarps with the same morphology on the insect body and the lethal rate by the fungus was $88{\pm}16%$. This fungus has over 99% homology with Cordyceps bassiana (imperfect fungal name is Beauveria bassiana) in ITS-5.8s rDNA base sequence. The fungal ecology and the infection process of the fungus into its host need to be clarified before using this fungus as a biological control agent.

• Journal of Mushroom
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• v.3 no.2
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• pp.71-74
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• 2005

The sterile form of Inonotus obliquus is used for preparation of the medicine befungin that is effective in the treatment of gastritis, gastric ulcers, and several tumors. The fungus is known to be produced mainly on the stems of Betula platyphylla var. japonica that grows at high altitudinal (above 1,100 m) region in Korea. But, we found the mushroom on the stem of Betula costata at Mt. Jumbong in Korea. We isolated a pure culture of the fungus from the stem of B. costata by use of potato dextrose agar (PDA) medium with streptomycin. We could isolate the fungus from plant's tissue filled with hyphae, but not from other parts. The spore collected from the sclerotia showed $6.0{\sim}10.0{\times}4.5{\sim}6.0{\mu}m$ in diameter, and the hypha was $2.5{\sim}5.0{\mu}m$ in thickness. The colony showed irregular features and scattered yellow color at the center as the culture ages. We could find brownish setae at the yellow region of colony at 20 days of culture, and the size ranged $4{\sim}6{\times}100{\sim}420{\mu}m$. The oatmeal agar (OA) provided best growth for I. obliquus among five media (CDA, CMA, MA, OA and PDA). Optimum temperature ranged $25{\sim}30^{\circ}C$, and optimum pH was relatively alkaline with the range of pH 8.0~9.5.

• Korean Journal of Environmental Agriculture
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• v.36 no.4
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• pp.299-305
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• 2017

BACKGROUND: Although the filamentous fungal pathogen Colletotrichum species causing anthracnose disease on various fruits including peach, apple, persimmon and grape, there is no report on Japanese plum in Korea. METHODS AND RESULTS: In 2016, diseased fruits showing typical anthracnose symptoms of Japanese plum were collected in market and ochards. Diseased tissue was cut off and disinfected subsequently with 70% ethanol for 1 min, and in 1% sodium hypochloride solution for 1 min, followed by three washes with sterile distilled water. The disinfected tissues were placed onto potato dextrose agar (PDA), and incubated at $25^{\circ}C$ in the dark for 5 to 7 days. For single-spore isolation, conidia were scraped off the plate using a loop, and suspended with 10 mL sterile distilled water. One hundred microliter of the conidial suspension was spread on PDA plates and incubated at $25^{\circ}C$. Finally, one germinated conidium was transferred onto PDA plates. Morphological and cultural characteries of colonies and spores of isolated Colletotrichum were observed after 7 to 10 days incubation on PDA. Molecular identification of isolates were analyzed by comparing rDNA-ITS gene sequences with NCBI GeneBank. CONCLUSION: Of eleven isolates of Colletotrichum isolated from anthracnose diseased Japanese plum fruits, six were identified as C. acutatum, and five as C. gloeosporioides based on diagnostic characteristics such as colony growth rate, shape and size of conidia, and rDNA-ITS sequences. This is the first report of Colletotrichum causing the anthracnose on Japanese plum in Korea.

• Korean journal of applied entomology
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• v.53 no.3
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• pp.287-293
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• 2014

Matsumuraeses phaseoli is one of the main pests that attack the flowers and pods of red bean (Vigna angularis) and mungbean (Vigna radiata) in Korea. To elucidate the developmental characteristics and over-wintering stage of M. phaseoli, several stages of the insect were observed through artificial rearing under outdoor conditions in Suwon ($37^{\circ}$16'N $126^{\circ}$59'E 35ASL), Korea. In colonies in which neonate larvae were reared at about 2-week intervals for more than a year, the developmental period from larva to adult emergence became longer from spring to summer, but shorter from summer to autumn; aestivation was not observed during the summer season. The colony in which rearing started on Oct 8, 2008 over-wintered as pupae and emerged in late April next year with a survival rate of 6%. However, the colony in which the rearing started on Oct 23, 2008 over-wintered as mature larvae, pupated in late April, and emerged in early and mid-May with a survival rate of 2%. When the fifth instar larvae were transferred outside from the laboratory ($25^{\circ}C$, 15L:9D) between November and February, no larvae could survive during the winter season. Some newly laid eggs and newly emerged adults could not hatch and could not survive, respectively, in outdoor conditions in November and December. These results suggest that neonate larvae of M. phaseoli that hatch in October can over-winter as late larvae or pupae in Suwon, Korea.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.389-396
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• 2000

To determine whether the Tricholoma matsutake (pine mushroom, Songyi) is symbiotic or parasitic to Pinus densiflora, structural change in their natural ectomycorrhizas were examined. The mycorrhizal samples were collected at three progressional points in the natural hypogeous colony(shiro) : colony front edge, near the fruiting point and 20cm back. The fine roots in the colonies were typical ectomycorrhizas with fungal mantle and Hartig net. However, the T. matsutake mycorrhizas had unique characteristics compared to other types of ectomycorrhizas. That is, spatially the fungal mantle and Hartig net of the T. matsutake mycorrhizas continued to develop along the growing tip, while temporally those structures declined to shrink changing to black brown in the older part of the roots behind the actively growing tip portion. However, there was no mark that the fungal hyphae penetrated into either the cortical cells, endodermal cell layers or stele. The apical tips of the blackened roots remained alive to form new mycorrhizas with other fungi later. Therefore, we conclude that the mycorrhiza of T. matsutake+P. densiflora is rather a dynamic symbiosis that changes its position spatiotemporally as the root grows than either a simple parasitism or symbiosis.

• Journal of Apiculture
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• v.32 no.3
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• pp.155-162
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• 2017

This research was carried out to evaluate the royal jelly production in Apis mellifera through the selection of superior honeybee lines. For the study, two inbred honeybee lines A and C were evaluated for the production of royal jelly by their workers, royal jelly production per colony (g), and the acceptance percentage of grafted larvae (%). The results showed that, the average royal jelly production per colony was highest ($33.7{\pm}7.41g$) in the inbred line C in comparison to other lines and the percentage of larvae acceptance ($87.8{\pm}7.5%$) was also highest in the inbred line C in comparison to other liens. The royal jelly produced by the three honeybee lines was analyzed for their trans-10-hydroxy-2-decenoic acid (10-HDA) content using a column liquid chromatography technique. Chromatographic results showed that the royal jelly produced by the inbred honeybee line C had the maximum amount of 10-HDA. We also observed age-dependent alterations of the major royal jelly proteins (MRJPs), which were differentially expressed in the two inbred lines and the commercial line, using quantitative real time-PCR (qRT-PCR).

• The Korean Journal of Mycology
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• v.43 no.1
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• pp.26-32
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• 2015

In this study, a new cultivar of Lentinula edodes was bred from dikaryotic KFRI 490 and monokaryotic KFRI 536 by Di-mon method. The new breed was named "Poongnyunko" and physiological characteristics was investigated. Its optimal growing temperature was $25^{\circ}C$, and it had thin density. Its colony was colorless and did not form any epithelium. On the $7^{th}$ day of mycelial growth, "Poongnyunko" was 56.6 mm, and showed higher cellulase activity compared with "Sanlim 4-ho"(52.9 mm). On the $5^{th}$ day of mycelial growth, "Poongnyunko" was 58.0 mm, and showed higher laccase activity compared with "Sanlim 4-ho" (55.6 mm). Its pH at a substrate was 6.0. Before cultivation, the pH of sawdust substrate was 4.7-5.5 went down to 3.7-3.9 after 120-day cultivation. After 60 days of cultivation, the change of $CO_2$ was the greatest. During the cultivation, $CO_2$ concentration in a growing bag was 4.67% to 3.90%.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.187-194
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• 2015

In this study, L. plantarum, when reacting with the culture media of potential pathogenic bacteria, exhibited an increase in growth rate and antimicrobial activity. In order to examine the characteristics and the nature of the reaction with the bacteria, this study carried out experiments involving culturing the test bacteria in M9 minimal media. Subsequently, the supernatant was incrassated by the decompression-drying method. Through colony forming unit assay, it was confirmed that L. plantarum had the function of growth inhibition to various bacteria. After culturing L. plantarum with bacterial media, the growth rate of L. plantarum was measured by absorbance (OD₆₀₀), the results showed that the growth rate (E. coli treatment group: OD₆₀₀ = 0.848, S. typhimurium treatment group: OD₆₀₀ = 0.848) increased, as compared with the non-treated control group (OD₆₀₀ = 0.48). In contrast, the concentrate itself did not induce the growth of L. plantarum. These results were observed as a universal phenomenon of the Lactobacillus species. Moreover, the increase in antimicrobial activity was observed in L. plantarum, which reacted with the culture media of E. coli and S. typhimurium, through a disc diffusion assay, and the result of growth inhibition against various bacteria was induced. Finally, based on the analysis results of the characteristics of bacteria culture media, which increased the growth rate of L. plantarum and antibacterial activity, the bacterial media had a tolerance for catabolic enzymes, pH 2−8 and heat. Therefore, this substance can be said to be a small molecule which is highly stable under various conditions.

• Journal of Mushroom
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• v.16 no.2
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• pp.61-64
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• 2018

This study was carried out to investigate the management characteristics and growth performance of L. edodes from the cooling stage to incubation. Bags of different heights and weights are available for bagging. When the medium size of $17{\times}13cm$ was used and the size of the inoculation hole was changed from 1/3 to 2/3, the browning period was shortened to 30 days. Mycelial growth was evaluated according to the cooling temperature after sterilization. It was observed to be the highest at 122 mm/15 days at $10^{\circ}C$ and 114 mm/15 days and 117 mm/15 days at $15^{\circ}C$ and $20^{\circ}C$, respectively. The contamination rate of the sawdust media before inoculation was measured as 0, $4.5{\times}10$, $1.3{\times}10^2$, $4.0{\times}10^3cfu$ at $5^{\circ}C$, $10^{\circ}C$, $15^{\circ}C$, and $24^{\circ}C$ respectively. The average of $1.6{\times}10^8$ colony forming units (cfu) of microorganisms was observed in the sawdust that had been piled for six months outdoors. In summer, the sawdust has to be used immediately after mixing. The sterilized medium had an average of $4{\times}10^3cfu$ of microorganisms at $24^{\circ}C$ and $1.3{\times}10^2cfu$ at $15^{\circ}C$. After 15 days of inoculation in vitro, the growth conditions of the sawdust was the best at 132 mm, followed by grain and liquid. When inoculated with liquid spawn, the moisture content of the substrate should be adjusted between 50% and 55% in advance.