• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.127-136
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• 2020

This study was conducted to investigate the population characteristics of Nile tilapia (Oreochromis niloticus) in the Daegu Metropolitan City thermal effluent stream (Dalseo Stream) from January to November 2019. The collected fish were identified as 4,247 individuals of 20 species from a total of eight families. The dominant species was O. niloticus with 1,306 individuals and a high relative abundance (30.75%). The water temperature of Dalseo Stream was maintained above 10℃ throughout the year, which means that O. niloticus could inhabit it even in winter. The length-weight analysis showed a regression coefficient b of 3.1496, and a condition factor (k) of 0.0025 with a positive slope. Comparing the water temperature of Dalseo Stream and the total length of O. niloticus per investigation period, the 0-age individuals appeared May 29 when the water temperature was maintained above 22℃. In conclusion, the thermal effluent of Dalseo Stream allowed O. niloticus to survive in winter and maintain stable growth conditions and life cycles. The results of this study will inform ecological information on O. niloticus, which suggests that river management efforts should consider the management of O. niloticus populations for the conservation of fish species diversity.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.4
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• pp.313-322
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• 2007

The object of this experiment was to investigate the food habits of dairy goats fed with various roughage sources. The experimental trials were conducted at Chungnam National University in 2007. The experimental roughages include five sources and 25 species in all; grass sources: 5 species (Lolium perenne, Festuca arundinacea, Poa pratensis, Agrostis alba and mixed grass, legume sources: 5 species (Trifolium pratense, Medicago sativa, Trifolium repens, Melilotus officinalis and Vicia villosa), browse sources : 5 species (Quercus serrata Thunb., Prunus jamasakura Sieb., Quercus aliena Blume, Robinia pseudoaccacia and Pinus densiflora), weed sources: 5 species (Artemisia princeps Pampanini, Erigeron canadensis, Alopecurus aegualis Sobolewski, Echinochloa crusgalli var. frumentacea (Roxb.) Wight and Rumex crispus), and native grass sources: 5 species (Zoysia japonica Steudel, Agropyron tsukushiense var. transiens (Hack) Ohwi., Arundinella hirta (Thunb.) Tanaka, Miscanthus sinensis Anderss and Phragmites comunis Trin). Ten dairy goats(Saanen) were selected which had nearly the same body weight(average 31kg). Experimental roughages were prepared by 0.5kg per 1 species fed to dairy goats, and the experiment was carried out from 09:00 to 18:00. The chemical composition and dry matter digestibility of each roughage source and species were significantly different at the sampling area, plant species, growth stages and cutting period. The dairy goats ate more roughages which had low fibrous contents, but high dry matter digestibility. Among all the 25 species of roughages, the favorite intake species order by dairy goat was observed like this: perennial ryegrass, tall fescue and red clover, respectively, and the lower intake species order was Rumex crispus. On the other hand, compared to each roughage source, total intake amount by dairy goats was showed as forage grasses (59.0%) which contained grasses(33.3%) and legumes (25.7%), browse (19.6%), weeds (15.9%) and native grasses (5.5%). Based on the result, the food intake type of dairy goats seems to be closer to grazer type.

• Journal of Life Science
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• v.19 no.6
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• pp.770-780
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• 2009

A new photosensitizer, 9-Hydroxypheophorbide-a (9-HpbD-a), was derived from Spirulina platensis. We conducted a series of experiments, in vitro and in vivo, to evaluate the anticancer effect and mechanism of photodynamic therapy using 9-HpbD-a and 660 nm diode lasers on a squamous carcinoma cell line. We studied the cytotoxic effects of pheophytin-a, 9-HpbD-a, 9-HpbD-a red and 660 nm diode lasers in a human head and neck cancer cell line (SNU-1041). Cell growth inhibition was determined by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. The effects of 9-HpbD was higher than those of 9-HpbD-a red or pheophytin-a in PDT. We then tested the cytotoxic effects of 9-hydroxypheophorbide-a (9-HpbD-a) in vitro. The cultured SNU-I041 cells were treated with serial concentrations of 9-HpbD-a followed by various energy doses (0, 0.1, 0.5, 3.2 J/$cm^{2}$) and by various interval times (0, 3, 6, 9, 12 hr) until laser irradiation, then MTT assay was applied to measure the relative inhibitory effects of photodynamic therapy (PDT). Optimal laser irradiation time was 30 minutes and the cytotoxic effects according to incubation time after 9-HpbD-a treatment increased until 6 hours, after which it then showed no increase. To observe the cell death mechanism after PDT, SUN-I041 cells were stained by Hoechst 33342 and propidium iodide after PDT, and observed under transmission electron microscopy (TEM). The principal mechanism of PDT at a low dose of 9-HpbD-a was apoptosis, and at a high dose of 9-HpbD-a it was necrosis. PDT effects were also observed in a xenografted nude mouse model. Group I (no 9-HpbD-a, no laser irradiation) and Group II (9-HpbD-a injection only) showed no response (4/4, 100%), and Group III (laser irradiation only) showed recurrence (1/4,25%) or no response (3/4, 75 %). Group IV (9-HpbD-a + laser irradiation) showed complete response (10/16, 62.5%), recurrence (4/16, 25%) or no response (2/16, 12.5%). Group IV showed a significant remission rate compared to other groups (p<0.05). These results suggest that 9-HpbD-a is a promising photosensitizer for the future and that further studies on biodistribution, toxicity and mechanism of action would be needed to use 9-HpbD-a as a photosensitizer in the clinical setting.

• Korean Journal of Poultry Science
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• v.38 no.2
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• pp.129-136
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• 2011

The objective of this study was to evaluate the effects of different levels of ${\alpha}$-tocopherol and selenium in broiler diets on performance and physicochemical properties of chicken thigh meat. A total of 360 broiler chicks divided into six groups were fed a basal diet (control) or basal diet supplemented with 50 IU ${\alpha}$-tocopherol/kg (T1), 100 IU ${\alpha}$-tocopherol/kg (T2), 200IU ${\alpha}$-tocopherol/kg (T3), 0.3 ppm selenium/kg (T4), and 100 IU ${\alpha}$-tocopherol/kg + 0.3 ppm selenium/kg (T5) for five weeks. Growth performance and proximate composition of chicken thigh meat were not influenced by all dietary treatments, except for crude fat, which was significantly lower in the treatment with ${\alpha}$-tocopherol or selenium, or both compared to control. The dietary ${\alpha}$-tocopherol and selenium supplementation had no significant effects on pH, CIE $L^*$ (lightness), and $b^*$ (yellowness) values but TBARS (thiobarbituric acid reactive substance) values were decreased (P<0.05) by the addition of ${\alpha}$-tocopherol and selenium. CIE $a^*$ (redness) values increased significantly with added ${\alpha}$-tocopherol and selenium relative to the control (P<0.05). Likewise, changes in fatty acid composition in chicken thigh meat with the dietary supplementations with ${\alpha}$-tocopherol, selenium and their combination significantly increased (P<0.05) unsaturated fatty acid, whereas saturated fatty acid were decreased. It was concluded that the addition of 200 IU ${\alpha}$-tocopherol (T3) and 100 IU of ${\alpha}$-tocopherol plus 0.3 ppm selenium (T5) were most effectiveness in the improvements in the lipid oxidative stability of chicken meat when compared to the control.

• Weed & Turfgrass Science
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• v.6 no.3
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• pp.179-188
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• 2017

In order to provide basic data for efficient control of weedy rice, we analyzed emergence rate of 100 weedy rice genetic resources collected in South Korea according to growth temperature and soil burial depth. Analyzing of emergence rate using low dormancy weedy rice genetic resources, emergence was increased at 12 and $14^{\circ}C$ of mean temperature condition. When calculating the effective accumulated temperature above $10^{\circ}C$, emergence rate increased 0.6% and 0.5% in 1 cm and 3 cm of soil depth, respectively according to increase of $1^{\circ}C$. However it reduced as 0.28% in 5 cm of soil depth condition. Analyzing of emergence rate using high dormancy weedy rice, red rice showed 55%, 46%, 41% of emergence rate in 1 cm, 3 cm and 5 cm of soil depth condition, respectively. However those of white rice decreased as 10%, 8% and 5.7% in 1 cm, 3 cm and 5 cm of soil depth condition, respectively. Relative emergence, assuming the final emergence rate as 100%, reached 80%, 90% and 100% when effective accumulated temperature was $83-112^{\circ}C$, $100-123^{\circ}C$, $148-160^{\circ}C$ respectively.

• Journal of Food Hygiene and Safety
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• v.35 no.5
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• pp.489-494
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• 2020

A total of 101 samples of convenience baby food products were analyzed by microwave digestion and mineral nutrients (iron, zinc, calcium, magnesium) were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES). By type, the samples included 44 rice porridges, 40 soft-boiled rices, 11 purees, and 6 powders. The mean values for iron (Fe) content were 0.05 to 0.45 mg/100 g (excepted powder type, mg/l0 g). This was equivalent to 22.35% for rice porridge, 10.55% for soft-boiled rice, 9.88% for puree and 2.74% for powder type compared to the KDRIs (Dietary Reference Intakes for Koreans), respectively. The mean values for zinc (Zn) was 0.06 to 0.28 mg/100 g (excepted powder type, mg/l0 g) and the KDRI ratio was the lowest at 5.94% in puree, with 27.76%, 28.95% and 10.91% in rice porridge, soft-boiled rice and powder type, respectively. Calcium (Ca) content relative to KDRIs was relatively low compared to other minerals, with 6.65% for rice porridge, 3.61% for soft-boiled rice, 6.24% for puree and 3.07% for powder type, respectively. The magnesium (Mg) content of baby food ranged from 13.4% to 39.0% compared to KDRIs, and was included in all baby food as a whole. For balanced nutritional mineral supply to infants, it is recommended that information on mineral sources and ingredients in convenience baby food be clearly provided to ensure proper growth and development.

• Korean journal of applied entomology
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• v.36 no.1
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• pp.77-82
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• 1997

This study was carried out to investigate the developmental characteristics and life cycle of sciarid fly (Lycoriella sp.), an important mushroom pest. The sciarid fly was reared ina growth chamber at 21$\pm$$1^{\circ}C$ and 55$\pm$5% of relative humidity with a 16h high, 8h dark cycle and Flammulina velutipes was used at diet. The egg was oval with 0.17 mm in diameter and 0.27 mm in length. Average egg period was 4 days. Body length of each instar from the 1st to 3rd was 0.7, 1.5, and 4.5, mm. respectively. Average weight of each instar was 1.9, 15.4 and 93.6 $\mu\textrm{g}$, respectively. In the 4th instar larvae, however, developmental characteristics of female and male became different by body length, weight and segment size. Body length and weight of the 4th instar female larvae were 5 mm and 162$\mu\textrm{g}$, and those of the male larvae were 3.5 mm and 90 $\mu\textrm{g}$, respectively. The larval periods of female and male were respectively 13.5 and13 days. Pupal length of female and male was 3.5 and 2.7 mm, and average weight was 136 $\mu\textrm{g}$ and 6.5$\mu\textrm{g}$, respectively. Adults were emerged from female and male pupae on 5.5 and on 5 days after pupation, respectively. Average longevity of male and female were 7 and 5 days, respectively. The weight of female was two-fold heavier than the male. After copulation, female laid approximately 130 to 150 eggs on/in the sporophore of mushroom. In conclusion, total lifespan of male and female were 29 and 28 days, respectively.

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.165-175
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• 2018

The purpose of this study is to provide the basic data such as distribution status, growth characteristics, and the structural characteristics of forest stands for the systematic conservation and management of relict forest trees (stem girth of 300cm or larger) established naturally in Gangwon Province, Korea. The survey showed that 434 individuals of 19 species (conifers: 228 individuals of 4 species, broad-leaved trees: 206 individuals of 15 species) were distributed in Gangwon Province, and Taxus cuspidata was the most abundant among them with 203 individuals or about 46.7 % of the total. The stem girth was average of 404cm (conifers: 373cm, broad-leaves: 421cm), and Tilia amurensis with multi-stemmed growing on Sorak mountain range had the largest stem girth at 1,113cm. The average height and the crown width of relict forest trees were 15.4m and 10.0m, respectively. Although the environments of relict forest trees showed a slight difference by species, the relative appearance frequencies of most trees were high in the environments where the altitude was higher than 1,000 m, slope degree was greater than $25^{\circ}$, the slope faced north, and microtopography was at the upper of slopes. Regarding the stand characteristics of relict forest trees per unit area ($/100m^2$), the average total coverage was 294% (max. 475%), the total average number of species was 36 species (max. 60 species), the average species diversity index (H') was 2.560 (max. 3.593), the average canopy closure was 84.8% (max. 94.6%), and the average basal area (/ha) was $52.7m^2$ (max. $116.4m^2$, relict trees $30.0m^2$, and other trees $22.7m^2$). The analysis of the dynamics of the forest stands where relict forest trees were growing showed four types of the maintenance mechanisms of relict forest trees depending on the supply pattern of succeeding trees: "Low-density but persistent type (Quercus mongolica, Abies holophylla, Tilia amurensis, and Pyrus ussuriensis)," "Long ago stopped type (Pinus densiflora)," "Recently stopped type (Abies nephrolepis, Quercus variabilis, and Betula schmidtii)," and "Periodically repeated types of supply and stop (Salix caprea and Quercus serrata).".

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.9-9
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• 2014

Null mutants generated by targeted gene replacement are frequently used to reveal function of the genes in fungi. However, targeted gene deletions may be difficult to obtain or it may not be applicable, such as in the case of redundant or lethal genes. Constitutive expression system could be an alternative to avoid these difficulties and to provide new platform in fungal functional genomics research. Here we developed a novel platform for functional analysis genes in Magnaporthe oryzae by constitutive expression under a strong promoter. Employing a binary vector (pGOF1), carrying $EF1{\beta}$ promoter, we generated a total of 4,432 transformants by Agrobacterium tumefaciens-mediated transformation. We have analyzed a subset of 54 transformants that have the vector inserted in the promoter region of individual genes, at distances ranging from 44 to 1,479 bp. These transformants showed increased transcript levels of the genes that are found immediately adjacent to the vector, compared to those of wild type. Ten transformants showed higher levels of expression relative to the wild type not only in mycelial stage but also during infection-related development. Two transformants that T-DNA was inserted in the promotor regions of putative lethal genes, MoRPT4 and MoDBP5, showed decreased conidiation and pathogenicity, respectively. We also characterized two transformants that T-DNA was inserted in functionally redundant genes encoding alpha-glucosidase and alpha-mannosidase. These transformants also showed decreased mycelial growth and pathogenicity, implying successful application of this platform in functional analysis of the genes. Our data also demonstrated that comparative phenotypic analysis under over-expression and suppression of gene expression could prove a highly efficient system for functional analysis of the genes. Our over-expressed transformants library would be a valuable resource for functional characterization of the redundant or lethal genes in M. oryzae and this system may be applicable in other fungi.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.25-25
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• 2014

Three species of Fusarium, F. fujikuroi, F. verticillioides and F. proliferatum, are known to be associated with bakanae disease of rice [1, 2]. F. fujikuroi infects rice flowers and survive in endosperm and embryo of the seeds. Infected seed is an important source of primary inoculum of pathogens [3]. Seeds of rice (Oryza sativa cv. Boramchan) collected from bakanae-infected field were found to be 96% infected with Fusarium sp., 52% with F. fujikuroi, 42% with F. verticillioides, and 12% with F. proliferatum as determined by incubation method and species-specific PCR assays. F. fujikuroi was detected at lemma/palea, endosperm and embryo whereas F. verticillioides and F. proliferatum were recovered only from lemma/palea by means of component plating test. Seed disinfection methods have been developed to control bakanae disease and prochloraz has been most widely used for rice seeds. Two chemicals formulated with prochloraz (PC 1) and prochloraz + hexaconazole (PC 2) that inhibit biosynthesis of ergosterol strongly reduced the incidence of Fusarium spp. on selective media to 4.7% and 2.0%, respectively. Disease symptoms of rice seedlings in nursery soil were alleviated by chemical treatment; seedlings with elongated leaves or wide angle between leaf and stem were strikingly reduced from 15.6 to 3.2% (PC 1) and 0 (PC 2), stem rots were reduced from 56.9 to 26.2% (PC 1) and 32.1% (PC 2), and normal seedling increased from 0.4 to 13.3% (PC 2). Prochloraz has some disadvantages and risks such as the occurrence of tolerant pathogens [4] and effects on the sterol synthesis in animals and humans [5]. For these reasons, it is necessary to develop new disinfection method that do not induce fungal tolerance and are safe to humans and animals. Chlorine dioxide ($ClO_2$), that is less toxic, produces no harmful byproducts, and has high oxidizing power, has been reported to be effective at disinfection of several phytopathogenic fungi including Colletotrichum spp. and Alternaria spp. [6]. Gaseous $ClO_2$ applied to rice seeds at a concentration of 20 ppm strongly suppressed mycelial growth of Fusarium fujikuroi, F. verticillioides and F. proliferatum. The incidence of Fusarium spp. in dry seed with 8.7% seed moisture content (SMC) tended to decrease as the concentration of $ClO_2$ increased from 20 to 40 ppm. Applying 40 ppm $ClO_2$ at 90% relative humidity, incidence was reduced to 5.3% and resulted in significant reduction of disease symptoms on MS media. In nursery soil, stem rot was reduced from 56.9 to 15.4% and the number of normal seedlings increased from 0.4 to 25.5%. With water-soaked seeds (33.1% SMC) holding moisture in the endosperm and embryo, the effectiveness of disinfection using $ClO_2$ increased, even when treated with only 20 ppm for four hours. This suggests that moisture was a key element for action of $ClO_2$. Removal of the palea and lemma from seeds significantly decreased the incidence of Fusarium spp. to 3.0%. Seed germination appeared to decrease slightly by water-soaking at $30^{\circ}C$ because of increased SMC and by physical damage of embryos from hulling. These results indicate that the use of gaseous $ClO_2$ was effective as a means to disinfect rice seeds infected with Fusarium spp. and that moisture around the pathogens in the seed was an important factor for the action of $ClO_2$. Further investigations should be conducted to ascertain the best conditions for complete disinfection of Fusarium spp. that infect deep site of rice seeds.