• Korean Journal of Ecology and Environment
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• v.48 no.1
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• pp.51-60
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• 2015

Forest vegetation of Youngbong (1,094 m) in Woraksan National Park is classified into mountain forest vegetation. Mountain forest vegetation is subdivided into deciduous broad-leaved forest, mountain valley forest, coniferous forest, riparian forest, afforestation and other vegetation. Including 84 communities of mountain forest vegetation and 7 communities of other vegetation, the total of 91 communities were researched; mountain forest vegetation classified by physiognomy classification are 39 communities deciduous broad-leaved forest, 26 communities of mountain valley forest, 6 communities of coniferous forests, 2 communities of riparian forests, 11 afforestation and 7 other vegetation. As for the distribution rate for surveyed main communities, Quercus mongolica, Quercus variabilis communities account for 40.879 percent of deciduous broad leaved forest, Fraxinus mandshurica - Cornus controversa community takes up 25.627 percent of mountain valley forest, Pinus densiflora community holds 75.618 percent of mountain coniferous forest holds. In conclusion, minority species consisting of Quercus mongolica, Pinus densiflora, Quercus variabilis, Fraxinus mandshurica, and Quercus serrata are distributed as dominant species of the uppermost part in a forest vegetation region in Woraksan National Park. In addition, because of vegetation succession and climate factors, numerous colonies formed by the two species are expected to be replaced by Quercus mongolica, Quercus variabilis and Fraxinus mandshurica which are climax species in the area.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.528-533
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• 2009

In the current study, the mesenchymal stem cells (MSCs) isolated and propagated from the human umbilical cord blood (UCB) were tested for their capabilities of differentiation into chondrocytes in vitro. The mesenchymal progenitor cells (MPCs) collected from UCB were cultured in a low glucose DMEM medium with 10% FBS, L-glutamine and antibiotics. The human MSC colonies were positively stained by PAS reaction. When the immunophenotypes of surface antigens on the MSCs were analyzed by fluorescence-activated cell sorter (FACS) analysis, these cells expressed positively MSC-related antigens of CD 29, CD44, CD 90 and CD105, whereas they did not express antigens of CD14, CD31, CD34, CD45, CD133 and HLA-DR. Following induction these MSCs into chondrocytes in the chondrogenic differentiation medium for 3 weeks or more, the cells were stained positively with safranin O. We clearly confirmed that human MSCs were successfully differentiated into chondrocytes by RT-PCR and immunofluorescent stain of type-II collagen protein. These data also indicate that the isolation, proliferation and differentiation of the hUCB-derived MSCs in vitro can be used for elucidating the mechanisms involved in chondrogenesis. Moreover this differentiation technique can be applied to developing cell-based tissue regeneration or repair damaged tissues.

• Journal of Veterinary Clinics
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• v.29 no.2
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• pp.141-147
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• 2012

This work describes the characteristics of $Malassezia$ $pachydermatis$ isolated from dog ear canals and the effect of essential oils on the growth of this organism. Sterile cotton swabs were used to collect specimens from the external ear canal and culture tests were performed to detect the population size of $Malassezia$ yeast. Using three different isolation media, included Sabouraud dextrose agar (SDA) to isolate common $M.$ $pachydermatis$, and SDA supplemented with olive oil (SDAO) and Leeming's medium (LM) to detect lipophilic yeast, $Malassezia$ spp were isolated from 14 of 18 dogs (77.8%); isolation rates were 33.3% in SDA, 72.2% in SDAO and 66.7% in LM media. All $Malassezia$ spp isolates were identified as $M.$ $pachydermatis$ according to results of PCR amplification, but gross colony morphology and SDA growth rates suggested four different subtypes. Large (LC) and medium colony (MC) types respectively describe large colony (diameter > 3 mm) and medium colony (around 2 mm) after 72 hour incubation, and small (SC) type refers to smaller colony (< 1 mm) even after 5 days incubation; lipid dependent colonies did not grow onto SDA. Large Colony type strains were isolated from 4, 11, and 11 samples, MC type strains from 2, 3 and 1 and SC type strains from 1, 2 and 1 in SDA, SDAO and LM, respectively. Lipid-dependent $M.$ $pachydermatis$ (Lipo) were isolated from 3 samples each in SDAO and LM. Anti-$M.$ $pachydermatis$ activity testing was done using disc-diffusion assays and well diffusion tests. Most essential oils inhibited the growth of $M.$ $pachydermatis$ in a range from 0.5% to 1.0% of essential oils. MIC90 and MIC50 were variable depending upon the nature of essential oils. Thyme oil was found to be highly effective in inhibiting the growth of $M.$ $pachydermatis$ in a range from 0.125% to 0.0625% while marjoram and then tea tree oil exhibited lower inhibitory capacity.

• The Korean Journal of Pharmacology
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• v.29 no.1
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• pp.139-148
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• 1993

Both SCC 12 and SCC 13 cell lines were derived from squamous cell carcinoma (SCC) of the skin (Wu and Rheinwald, 1981). In the present study, we compared the inherent invasive activity in their raft cultures where most in vivo characteristics of epidermis can be reproduced by cell culture method. The raft culture of SCC 12 cell line produced many invading colonies within the collagen lattice and basal-like cells in the middle of differentiating cell layers, but no invasive activity was observed in the SCC 13 raft culture. We investigated which factors are implicated in inherent invasive activity of SCC 12 cell line by examining basal levels of type I collagenase, EGF receptor, fibronectin, and its receptor in two cell lines. Among them, only type I collagenase was significantly higher in invasive SCC 12 cells than in non-invasive SCC 13 cells. Furthermore, we tried to investigate mechanisms underlying between SCC 12 cell's inherent invasive activity and its high basal level of type I collagenase. As one of them, discrepancy in TGF alpha mediated responses between two cell lines was observed. In SCC 13 cells, TGF alpha initially stimulated type I collagenase at 12 h after TGF alpha treatment and then its down regulation was followed from 24 h even though TGF alpha was continuously present in the medium. However in SCC 12 cells, TGF alpha continuously stimulated type I collegenase up to 48 h. We propose that defect in EGF receptor's down-regulation may be involved in lack of type I collagenase's down-regulation and its possible connection to invasive activity of SCC 12 cell line.

• The Korean Journal of Pesticide Science
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• v.18 no.3
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• pp.202-209
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• 2014

RNA interference (RNAi) is the method which controls phenotypes of gene in live cells. Chitinase is the enzyme helping digestion and absorption of old cuticles during the ecdysis of insects. In order to investigate molting-inhibition effect with the chitinase related gene in Spodoptera litura, RNA was extracted from the $5^{th}$ instars. cDNA was synthesized and then we obtained about 700 bp size chitinase. After PCR products were cloned into a pGEM T-easy vector, colonies were picked. DNA was extracted from the colony cultures. EcoR I enzyme was used to check whether PCR products were inserted or not. And then we confirmed vector band of about 3 kb and insert band of about 700 bp. To synthesize the dsRNA, each DNA was cut with Spe I and Nco I enzymes (Circular DNA became lineared DNA). After synthesis of dsRNA, approximately 5 ul dsRNA was injected into the $3^{rd}$ abdominal segment of S. litura $4^{th}$ larvae. The concentration of dsRNA was about $10{\mu}g/{\mu}l$. We confirmed larval-larval molting : there were phenotypically abnormal individuals - for instance malformation, molting inhibition and change of integument color. Pupaadult molting : there were phenotypically abnormal individuals - for instance molting inhibition, change of wings and malformation. Also we could investigate the pupation, emergence and variation about noninjection, treated with DW and dsRNA. Each pupation was non-injection 83.3%, DW 78.3% and dsRNA 66.7%. Each emergence was non-injection 90.0%, DW 72.3% and dsRNA 65.0%. So we considered that chitinase dsRNA induced molting inhibition effect. But each variation was non-injection 8.9%, DW 2.9% and dsRNA 19.2%. Therefore dsRNA group showed the highest variation value. When 18 hours after injecting dsRNA, we could obtain abnormal individual.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.115-121
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• 2002

To develop a new method of conjugation and to determine the distribution of R plasimds, we isolated multi-drug resistant strains from fish pathogenic bacteria in the farms of south and east seacoasts of Korea. Out of the 134 isolates examined, 10 showed resistance to chloramphenicol, tetracycline, streptomycin, ampicillin, colistin, nalidixic acid, oxolinic acid and kanamycin. One out of 10 multi-drug resistance bacteria, Vibfio damsela JE1 (V. damsela JE1), contained transferable R plasmid of chlorarnphenicol- tetracycline resistance genes and other nucleic acids encoding ampicillin and kanamycin resistance. The presence of the R plasmid was confirmed by conjugation using the chromocult medium (CC) as a selective and differential medium for transconiugants with identification based on the growth or colors of the colonies. The frequency of R plasmid transfer with filter mating method was come out much higher than that of broth mating method and appeared to be dependent upon the mating time and temperature. The optimum conditions for filter mating method were found to be 30$^{\circ}C$ and 24hrs as mating temperature and period, respectively, Moreover, donor cells with R plasmid, both isolate and standard bacteria, were shown to have an ability to transfer the plasmid against Escherichia coli K-12 HB101 (E. coli HB101) and Edwardsiella tarda (E. tarda) RE14 at fairly high frequencies, finally, we isolated 3 isolates of Sphingomonas sp., carrying R plasmid from 12 multi-drug resistant bacteria in normal microflora of the flounder (Paralichthys olivaceus) group used for the isolation of V emsela JE1 four months before. The same size and gene transfer chayateristics of R plasimds with those of V damsela JE1 confirmed that normal microflora have the reservoir activity for R plasmid in natural aquatic environment.

• Restorative Dentistry and Endodontics
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• v.30 no.5
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• pp.409-422
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• 2005

The aim of this study was to identify the bacteria isolated from acute endodontic lesions by cell culture and 16S rDNA sequencing. The necrotic pulpal tissue was collected from 17 infected root canals, which were diagnosed as being either an acute pulpitis or acute periapical abscess. Samples were collected aseptically from the infected pulpal tissue of the infected root canals using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing 500 ul of 1 XPBS. The sample solution was briefly mixed and plated onto a BHI-agar plate containing $5\%$ sheep blood. The agar plates were incubated in a $37^{\circ}C$ anaerobic chamber for 7 days. The bacteria growing on the agar plate were identified by 16S rRNA coding gene (rDNA) cloning and sequencing at the species level. Among the 71 colonies grown on the agar plates, 56 strains survived and were identified. In dental caries involving the root canals, Streptococcus spp. were mainly isolated. Actinomyces, Clostridia, Bacteroides and Fusobacteria were isolated in the periapical lesion without dental caries. Interestingly, two new Actinomyces spp. (ChDC B639 and ChDC B631) were isolated in this study. These results showed that there was diversity among the species in endodontic lesions, This suggests that an endodontic infection is a mixed infection with a polymicrobial etiology. These results may offer the bacterial strains for pathogenesis studies related to an endodontic infection.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.8
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• pp.960-964
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• 2007

This study was performed to examine the toxicity of Psoralea corylifolia L. by the single-dose oral toxicity tests in rat and bacterial reverse mutation assay. In single-dose oral toxicity tests, 5 mL ethanol extract of P. corylifolia L. were directly injected into 10 rats (5 males and 5 females) at a dosage of 2 g/kg. Death practice was not detected during breeding periods (14 days), and $LD_{50}$ was calculated over 2 g/kg. No difference were observed with control group in the growth rate and histological observations. In bacterial reverse mutation assay, his(-) Salmonella Typhimurium TA98, TA100, TA1535, TA1537 and trp(-) Escherichia coli WP2uvrA (pKM101) were used for assessing the toxicity of ethanol extracts of P. corylifolia L.. No significant difference in formation of the colonies and no dose-dependent increase was observed regardless of the addition of S9 mix. The results showed that ethanol extracts of P. corylifolia L. did not have single-dose oral toxicity and mutagenic toxicity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.3
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• pp.379-389
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• 2008

This study was conducted to assess the microbiological quality of raw and cooked foods served in the elementary school food service. Raw and cooked food samples were collected from 11 selected elementary schools in both June to July and September to October of 2005. Petrifilm plates were used to determine (in duplicate) total aerobic colony counts (PAC), Enterobacteriaceae (PE), coliform counts (PCC), and E. coli counts (PEC). Heavy contamination of Enterobacteriaceae (from 0.08 to 7.40 log CFU/g) and total coliform (0.50 to 6.52 log CFU/g) were observed in raw materials and cooked foods. Escherichia coli (E. coli) were detected in the sample of currant tomato (3.70 log CFU/g), sesame leaf (3.59 log CFU/g), dropwort (0.20 log CFU/g), crown daisy (3.15 log CFU/g), parsley (3.00 log CFU/g), peeled green onion (1.74 log CFU/g), frozen pork (0.65 log CFU/g), frozen beef (0.20 or 1.50 log CFU/g), chicken (1.78 log CFU/g), and young radish leaf seasoned with soybean paste (1.24 log CFU/g). Multiplex PCR system was used to determine the food-borne pathogens: Salmonella spp., Bacillus cereus (B. cereus), E. coli O157:H7, Staphylococcus aureus, Listeria monocytogenes (L. monocytogenes), Vibrio parahaemolyticus, Campylobacter jejuni (C. jejuni), Shigella spp., B. cereus was detected in 19 samples of raw materials and 8 samples of cooked foods. With regard to quantitative analysis, B. cereus counts exceeded 5.46, 3.48 and 1.79 log CFU/g in sesame leaf, peeled green onion and seasoned mungbean jelly, respectively. E. coli O157:H7 was detected on 2 samples of frozen beefs, and its biochemical characteristics of one beef sample was confirmed with API 20E kit (93.7%). L. monocytogenes was detected in fried rice paper dumpling, but the presumptive colonies were not detected onto the conventional plate. C. jejuni was detected in peeled & washed onion.

• Korean journal of applied entomology
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• v.59 no.3
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• pp.185-202
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• 2020

The diapause induction season in Ostrinia furnacalis (Lepidoptera: Crambidae) was estimated in Suwon. Three batches of adult generations were observed, the first one from early May to early July, the second from early or mid-July to early or mid-August, and the third from mid-August to October. In outdoor larval rearing, colony rearing occurring from mid-July to mid-August produced both non-overwintering and overwintering larvae, whereas late-reared colonies produced only overwintering larvae. Larvae collected during July and August in maize fields produced both non-overwintering and overwintering larvae, whereas late-collected larvae produced only overwintering larvae. The results indicated that O. furnacalis has a bi- or trivoltine complex life cycle in this area. In the laboratory, when larvae of all instars within 9 h after molting were first treated to a diapause induction condition (11:13 h = light:dark photoperiod and 20℃), almost all larvae were induced to diapause. However, when similar treatments were conducted age-specifically for the 5th instar larvae, diapause induction rates in 3- and 4-day-old larvae of the 5th instar decreased. In contrast, when larvae were subjected to the diapause induction treatment only during the periods from the hatching stage to the 2nd, 3rd, and 4th instar, almost all larvae were not induced to diapause. The results suggest that the early age of the 5th larval instar is the last stage for sensitivity to diapause induction stimuli. In the diapause-induced larvae, hemolymph trehalose content increased and body supercooling points dropped, compared with those in non-diapause larvae.