• Korean Journal of Pharmacognosy
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• v.41 no.2
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• pp.103-107
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• 2010

Extensive phytochemical investigation of the methanol extract from the whole plant of Youngia japonica (Asteraceae) led us to the isolation of a new guaiane-type sesquiterpene (1), together with three related guaianolides, youngiajaponicoside A (2), crepiside H (3) and crepeside E (4). The chemical structure of 1 was elucidated by the aid of spectroscopic analyses including 2D-NMR experiments (COSY, HMBC, HMQC and ROESY). The isolated components (1-4) were evaluated for the inhibitory effect on the proliferation of four cultured human tumor cell lines such as A549, SK-OV-3, SK-MEL-2 and HCT-15, in vitro.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.551-556
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• 2020

Eel Anguilla japonica is an economically important inland culture fish species in East Asian countries, particularly in Korea, Japan, China, and Taiwan. In this study, the effects of feeding frequency on larval growth and survival rate were investigated. Eel larvae (average length, 6 mm) were fed a slurry-type diet containing shark eggs three, five, seven, or nine times per day. Survival rates differed significantly among the four experimental groups. Feeding frequencies of at least five and seven times a day were required until 15 and 30 days after hatching, respectively, to maintain an acceptable survival rate. Leptocephalus growth improved with increased feeding frequency until 15 days after hatching. The results suggest that providing an opportunity for early food intake enhances eel survival and growth in the early leptocephalus stage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.338-343
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• 1997

The response of seventy-five rice cultivars to ozone (O$_3$) were tested in the open-top chamber with ozone producing and monitoring system to determine the varietal difference of resistance to $O_3$ stress. Ozone was produced by electrostatic discharge in oxygen and was monitored by UV absorption ozone analyzer. Difference in response of rice to ozone was more clearly appeared on rice plants treated for 2 to 4 hours at 0.3 ppm concentration of $O_3$. Varietal resistance of rice to ozone was more distinctly classified at 21- to 35-day seedlings compared with 14-day rice plants. Most of indica and Tongil(indica$\times$japonica) type rice cultivars were more resistant than that of japonica cultivars based on the leaf injury to $O_3$. Eight Korean cultivars belong to japonica groups showed highly resistant reaction to $O_3$. Ozone exposure during booting stage caused lower grain fertility than exposures during seedling, maximum tillering and heading stages of rice.

• Asian Journal of Turfgrass Science
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• v.4 no.1
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• pp.5-11
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• 1990

Korean Lawn. Zoysia japonica Steud. is the type of a perennial warm-season turfgrass keeping green leaf color for 5 months from May to September in natural condition in Korea. This Studies were carried out to obtain the effects of N-P-K fertilization, regrowth capacity after mowing and chlorophyll contents on prolongation of the green leaf color period in Zoysia japonica Steud turfgrass areas. The results obtained are summarized as follows ; 1.The effects of nitrogen fertilizer application in Zoysia japonica Steud, turfgrass areas were affected on regrowth ability after mowing green color of leaf canopies and chlorophyll contents, respectively(P<.05) 2.A experimental plots which applied 51 g/m$^2$/10 weeks of N$_3$P$_1$K$_1$fertilizer, there were high significant effects on prolongation of the green leaf color period and the plots of phosphorus and potassium had additive effects. 3.Prolongation of the green leaf color period to the last of October was obviously possible by slow degrees in proportation to increment of the fertilizer. However, it is interpreted that more prolongation of the green period is impossible with N-P-K fertilization and irrigation treatments. unless the intermediate turfgrasses between $C_3$ and $C_4$plants must be found and bred.

• Journal of agriculture & life science
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• v.50 no.1
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• pp.105-115
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• 2016

This study was carried out to establish the optimum forest management plan for the Cryptomeria japonica plantations in southern inland and Jeju island in Korea. Sixty seven circular sample plots of 0.04ha were established and we surveyed vegetation structure and growth characteristics from three layers(upper, middle, and lower). As a result of cluster analysis obtained by importance values of each tree species, the community type of C. japonica stands were classified into C. japonica group(C1) and C. japonica-C obtusa group. C. obtusa community were also sbudivided into P. thunbergii-Q. serrata group(C2) and Q. serrata-C obtusa group(C3). In tree layers importance value(IV) of C. japonica were 97.2% in C1, 80.7% in C2, and 47.6% in C3 and in sub-tree layers IV were 8.9% in C1, 15.2% in C2, and 5.7% in C3. Especially in C3 there are bamboo species (Smilacina japonica var. lutecarpa and Pseudosasa japonica) it is necessary for us to control them. In shrub layers C. japonica were found in C1(9.2%) and C2(7.0%), but except for C3. In tree layer species diversity indices of each community ranged from the lowest 0.059 in C1 to the highest 0.548 in C3. Dominance ranged from 0.958 in C1 to 0.393 in C3 which may caused by interspecific competition. Current annual increment of diameter growth ranged from 7.01mm/yr to 8.04mm/yr. As a result of our study we recommend the application of proper thinning and pruning for C1 and C2.

• Journal of fish pathology
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• v.3 no.2
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• pp.61-66
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• 1990

Experimental infection and histopathological study using a deleterious aquatic fungus (Saprolegnia diclina type I) were carried out in the eels (Anguilla japonica) to know what pathological changes the fungus would produce in the affected eels. The eels in group A and B which were treated with fish net were not susceptible to experimental infection. In group C which the cuticle was scraped by artificial treatment, the aquatic fungi were invading all the eel bodies including the desquamated lesions. Histopathologically, the affected eels were markedly reduced in number of goblet cells and showed moderate damage of the clavate cells. Nodular formation involving ecchymotic hemorrhage was seen in some affected areas. The eels survived to 25 days after experimental infection.

• Proceedings of the Korean Society of Crop Science Conference
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• 1986.06a
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• pp.48-49
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• 1986

• Proceedings of the PSK Conference
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• 2000.04a
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• pp.111.1-111.1
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• 2000

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.1
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• pp.13-23
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• 2016

This study was conducted to investigate the growth characteristics of warm-season turfgrasses and to find out suitable turfgrass species on Saemangeum reclaimed land. Twenty native zoysiagrass(Zoysia sinica, Z. matrella, Z. japonica, Medium-leaf type zoysiagrass(hybrid zoysiagrass)) and bermudagrass(Cynodon dactylon) collected from Korea were used in this study. Total stolon length and the number of stolon per square meter, relative growth rate of shoot and stolon, and coverage rate were analyzed for 2 year. C. dactylon showed not only the most growth response with high relative growth rate of shoot and stolon, which were 19.9% and 66.3%, but also resulted in higher level of turf visual quality compared to others. Whereas Z. japonica showed the least growth response with low relative growth rate of shoot and stolon, which were 2.4% and 0.7%. Although all warm-season turfgrasses took root and grew up well, there were different growth rates between the interspecies. Z. sinica 'Z2034', Z. matrella 'Z4091', Z. japonica 'Z1064', Medium-leaf type zoysiagrass 'ZN6019' and C. dactylon 'BN7014' were the greatest growth rate of shoot and stolon. These results will be useful for selecting salt tolerant breeding lines and also used to develop a turfgrass cultivar with strong salinity tolerance through continuous monitoring.

• Korean Journal of Pharmacognosy
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• v.31 no.2
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• pp.163-167
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• 2000

Cordyceps is reputed for its broad biological activities and as a tonic for replenishing vital function in Chinese traditional medicines. As an attempt to obtain fundamental data for the development of a new type Cordyceps, the effects of the fruiting bodies of cultivated fungus of Paecilomyces japonica grown on silkworm larvae on hyperglycemia induced by streptozotocin(STZ) and by epinephrine in rats and in mice as well as on immunological functions in mice were investigated. The 70% methanol extract of the fungus, when administered orally at 100 and 300 mg/kg in STZ-induced hyperglycemic rats, caused a significant decrease in blood glucose level 3hr after sample treatments. The methanol extract, when administered p.o. at the same dose levels in epinephrine-induced hyperglycemic mice, also caused a significant decrease in serum glucose levels as well as a significant reversal of the liver glycogen contents suggesting its hypoglycemic activity might be due to glycogen breakdown in the liver. Treatment of normoglycaemic mice with the methanol extract of the fungus exhibited a significant glucose tolerance up to 3hr after oral glucose load(2.0 g/kg). The methanol extract also showed immuno-stimulating activity as measured by carbon clearance in mice and a significant antifatigue effect as measured by weight loaded forced swimming performance in mice.