• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.5
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• pp.383-391
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• 1992

A comparative study of enzymatic properties between the trypsin from the cat-shark Cephaloscyllium umbratile ( C-T) and the two trypsins from the mackerel Scomber japonicus $(M-T_A\;and\;M-T_B)$ was carried out following after the previous paper(Pyeun et al., 1991). Trypsin from cat-shark(C-T) showed the higher heat stability compared to the others $(M-T_A\;and\;M-T_B)$ and its denaturation constant$(K_D)$ was $10.68\times10^{-4}\;sec^{-1}\;at\;55^{\circ}C$ with BA-p-NA substrate. The activation energies(Ea) of the trypsins measured at a temperature range from $30^{\circ}C\;to\;50^{\circ}C$ were estimated to be 4.07 kcal/mole for C-T, 11.61 kcal/mole for $M-T_A$, and 8.43kcal/mole for $M-T_B$, respectively. The Km values were $24.9\times10^{-5}\;M\;for\;C-T,\;5.37\times10^{-5}\;M\;for\;M-T_A,\;and\;9.65\times10^{-5}\;M\;for\;M-T_B$. On the other hand, the Ki values for TLCK and DFP determined by Dixon plot were $1.50\times10^{-6}\;M\;and\;9.28\times10^{-6}\;M\;for\;C-T\;2.86\times10^{-6}\;M\;and\;2.11\times10^{-4}\;M\;for\;M-T_A\;and\;3.90\times10^{-6}\;M\;and\;1.60\times10^{-4}\;M\;for\;M-T_B$ Similar amino acid profiles were showed between three trypsins each other, with few exceptions of $M-T_B$ containing higher amount of arginine, and the smaller amount of tryptophan in C-T than the others.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.412-420
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• 1995

Oxygen consumption (OC), ammonia nitrogen (AN ) excretion and body composition were measured to study the effects of energy/protein ratio (EPR) on the utilization of protein and energy in juvenile rockfish, Sebastes schiegeli. Juvenile rockfish were divided into three groups that they fed three isocaloric diets (3,5kcal/g) containing 30 (I), 40 (II) or $50\%$ crude protein (III). EPR of the three experimental diets were 11.5 (I), 8.7 (II) and 7.0kcal/g III), respectively. Juvenile rockfish (wet wt. 2.9-3.1g) were cultured in 501 aquaria with the constant environmental condition of $20-24^{\circ}C$ water temperature and $34\%o$ salinity. For 24 hr after feeding the diets, juvenile rockfish fed diet III had a higher OC than did the fish from groups fed diets I and II, and average OC of the fish fed diets I, II and III were $0,93\pm0.02^a,\;0.92\pm0.02^a\;and\;1.03\pm0.03^bml\;O_2/g/h$, respectively. AN responses of juvenile rockfish to increasing levels of dietary protein (decreasing dietary EPR) were significantly different among three groups in which dietary protein at elevated levels increased the excretion of AN for 24 hr after feeding the diets. Average AN excretion of the fish fed diets I, II and III were $9.14\pm0.39^a,\;12.41\pm 0.53^a\;and\;14.89\pm0.55^c\;{\mu}g\;N/g/h$ respectively. The body protein content of the fish fed diet II for 59 days was significantly higher than that of the fish fed the other diets. But, there were no significant differences between three groups in body lipid, carbohydrate and ash contents. These results indicate that EPR of 9.7kcal/g (diet II) could be a optimum EPR in juvenile rockfish diet.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.7
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• pp.699-705
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• 2010

In this study, three different biological activated carbons (BACs) were prepared from activated carbons made of each coal (F400, Calgon), coconut (Samchully) and wood(Pica, Picabiol) which were run for two and half years in the pilot plant. The attached bio-film microorganisms in and on the BACs were isolated and identified. The results showed that nine different bacteria species (Chryseomonas luteola, Stenotrophomonas maltophilia, Pseudomonas vesicularis, Aeromonas hydrophila, Spingomonas paucimobilis, Agrobacterium radiobacter, Pseudomonas fluorescens, Spirillum spp., and Pasteurella haemolytica) were isolated and identified, the dominant species was Pseudomonas sp. that had occupied 56.5%. More specifically, it was observed that the populations of the microorganisms deceased in the order: Pasteurella haemolytica (18.9%) > Chryseomonas luteola (4.0%) > Agrobacterium radiobacter (3.5%) > Aeromonas hydrophila (2.0%) in and on the BACs. After isolating of 9 species of biofilm microorganisms, the growth curve for the biomass was investigated. During 24~96 hours, the biomass has the highest concentration, and activity of the biomass was the best to uptake geosmin as carbon resources. The operation temperatures for investigating the biodegradation of geosmin were set at $4^{\circ}C$ and $25^{\circ}C$. Pseudomonas vesicularis, Pseudomonas fluorescens, Agrobacterium radiobacter and Stenotrophomonas maltophilia played a maior role in removing the target compound as geosmin. However, geosmin was not biodegraded well by Chryseomonas luteola, Spingomonas paucimobilis, and Spirillum spp.. It is also interesting to evaluate kinetics of biodegradability of geosmin. The first-order rate constants for biodegradability of geosmin at $4^{\circ}C$ and $25^{\circ}C$ were $0.00006{\sim}0.0002\;hr^{-1}$ and $0.0043{\sim}0.0046\;hr^{-1}$ respectively. Higher water temperature produced better geosmin removal rates. When concentrations of geosmin increased from 10 to 10,000 ng/L, the rate constants for biodegradability of geosmin increased from 0.0003 to $0.0882\;hr^{-1}$. As described earlier, higher geosmin concentration in the reactor produced higher rate constant.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.2
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• pp.76-88
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• 2012

In order to investigate the distribution of water masses and spatio-temporal variation of nutrients in the coastal areas of Gangwon province of the Korean East Sea, a survey of the physico-chemical parameters (temperature and salinity) and nutrients ($NO_2$-N, $NO_3$-N, $NH_4$-N, $PO_4$-P, and $SiO_2$-Si) was carried out at 5 locations (Goseong, Sokcho, Yangyang, Gangneung, and Donghae) in February, May, August, and November 2009. The water masses included in the study area were divided into 4 groups; 1) Tsushima Surface Water (TSW), 2) Tsushima Middle Water (TMW), 3) North Korean Cold Water (NKCW), and 4) East Sea Proper Water (ESPW). The distribution of water masses was affected by the change of season. In February, surface water was derived from the TMW. The TSW was not observed in May, but only observed in August. In November, as the influence of the TSW weakened, that of the NKCW strengthened. Considering the vertical profiles of nutrients, the concentrations in all the seasons were very low within the surface water, but increased rapidly near the thermocline. Most of nutrient concentrations, except for dissolved silicate, remained constant below the depth of 200 m. However, the dissolved silicate concentration increased with depth, suggesting that silicate has a delayed regenerative pattern. The ESPW had the highest nutrient concentration, followed by the NKCW, TMW, and TSW. In February, May, and November, the N/P ratio in most of the water masses was similar to or larger than the Redfield ratio, indicating that nitrogenous nutrients did not act as a limiting factor for phytoplankton growth. However, in August, the N/P ratio in the TSW was less than the Redfield ratio, and the concentration of $NO_2$-N+$NO_3$-N was 0.86 ${\mu}m$, indicating that nitrogenous nutrients did act as a limiting factor for phytoplankton growth in the study area.

• Applied Biological Chemistry
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• v.19 no.1
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• pp.36-40
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• 1976

The mucilage of the root of Abelmoschus manihot, MEDIC is important for production of Korean traditional hand-made paper. This study was proceeded to detect the variation of the amount of free reducing sugars and of the viscosity in the mucilage. The results as follow. 1. The mucilage of the root of Abelmoschus manihot, MEDIC has contained some of free reducing sugars, 2. The viscosity of the mucilage isolated from the root decreases with time at the constant temperature, but the amount of reducing sugars show a little change. 3. The amount of the reducing sugars is not changed on the agitation. 4. When $1{\sim}2%$ ammonium sulfate solution is added, the viscosity of the mucilage decreases very gradually, and the amount of the free reducing sugars in the mucilage shows a little change.

• Korean Journal of Materials Research
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• v.11 no.8
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• pp.708-712
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• 2001

Microwave dielectric properties of $(Pb_{0.2}Ca_{0.8})[(Ca_{1/3}Nb{2/3})_{1-x}Ti_x]O_3$ ceramics were investigated as a function of $Ti^{4+}$ content (0.05$\leq$x$\leq$0.35). A single perovskite phase was obtained from x=0.05 to x=0.15, and $TiO_2$ and $CaNb_2O^6$ were detected as a secondary phase beyond x=0.2. The structure was changed from orthorhombic at x=0.05 to cubic at x=0.35. Dielectric constant(K) was increased with increase of $Ti^{4+}$ content due to increase of rattling effect, and was inversely proportional to the cube of the average radius of B-site cation, however, Qf value was decreased, which was due to the decrease of grain size and the secondary phase. With the increase of $Ti^{4+}$ content, the temperature coefficient of resonant frequency(TCF) was controlled from -27.36 ppm/$^{\circ}C$ value to +18.4 ppm/$^{\circ}C$ value, which was caused by the influence of tolerance factor(t) and the bond valence of B-site. Typically, K of 51.67, Qf of 7268(GHz), TCF of 0 ppm/$^{\circ}C$ were obtained in the $(Pb_{0.2}Ca_{0.8})[(Ca_{1/3}Nb_{2/3})_{0.8}Ti_0.2]O_3$ sintered at 13$50^{\circ}C$ for 3h.

• Korean journal of applied entomology
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• v.43 no.4 s.137
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• pp.297-304
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• 2004

The development of Aphidoletes aphidimyza, an aphidophagous gall midge, was studied at various constant temperatures ranging from 15 to $35^{\circ}C$, with $65{\pm}5\%$ RH, and a photo-period of 16L:8D. When A. aphidimyra was fed either on Aphis gossypii or Myzus persicae, it took 43.9 and 44.5 days, respectively, to develop from egg to pupa at $15^{\circ}C$, whereas at $25^{\circ}C$, 14.3 and 15.8 days. The developmental zero was 10.7 and $10.0^{\circ}C$, respectively, while the effective accumuative temperatures were 210.8 and 245.5 day-degrees. The nonlinear shape of temperature-dependent development, shown by A. aphidimyza when fed on either species of the aphids, was well described by the modified Sharpe and DeMichele model. When distribution model of completion time of development for each growth stage was expressed as physiological age and fitted to the Weibull fuction, the completion time of development gradually shortened from egg to larva, and to pupa. In addition, the coefficient of determination $r^2$ ranged between 0.86-0.93 and 0.85-0.94, respectively providing a good approximation of cumulative developmental rates. The life span of adult was 8.7 and 9.2 days at $15^{\circ}C$, and 3.1 and 2.7 days at $30^{\circ}C$, respectively. Egg incubation period was relatively short at $35^{\circ}C$ but hatchability was less than $50\%$ and the mortality of the larva at $35^{\circ}C$ reached $100\%$. At $30^{\circ}C$, the time of development lengthened and the adult longevity was short suggesting ill effect of high temperatures. Even though the life span of adults at $15^{\circ}C$ was relatively long, none moved freely in the rearing cage and no oviposition occurred. Accordingly, in case A. aphidimyza is adopted to suppress phytophagus aphid populations, it could be applicable to cropping systems with ambient temperatures above $20^{\circ}C$ and below $30^{\circ}C$. Within this range, A. aphidimyza adults was observed to be active and oviposit fully.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.79-85
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• 1981

As one of the fundamental studies for the breeding of marine algae, the effects of several plant hormones (IAA, Gibberellin, 2.4-D, NAA, Kinetin) on the growth of Porphyra-fronds, P. tenera Kjell. form tamatsuensis Miura, were investigated from January 21 to February 21 1981. The fronds used for the experiment were dissected out at $25mm^2$ size, and cultured in modified Provasoli's ESP medium supplemented with various concentrations of each plant growth regulators. The culture was kept under constant water temperature of $5^{\circ}C$ in 14 hrs. photoperiod and illuminated with 2,400 lux by fluorescent light. Based on the results of first experiment, the culture of fronds for the secondary experiment was carried out at $5^{\circ}C\;and\;10^{\circ}C$ in medium containing various levels of Kinetin from April 6 to 24, and compared the growth of two groups at each concentrations with each other, The results obtained are summarized as follows : (1) The best growth efficiencies were observed at 5.0mg/1 of each plant hormones except Gibberellin. Among them, the highest growth-rate was $312.5\%\;(345.3\%\;in\;frond\;size)$ in contrast with control at 5.0mg/1 of Kinetin, and was followed by $257.5\%\;(236.1\%)$ in 2.4-D,$166.7\%(147.6\%)$ in IAA and $141.7\%\;(167.7\%)$ in NAA, but that in Gibberellin was $247.9\%(241.9\%)$ at 10.0mg/l. (2) Especially, the fronds cultured at 5.0mg/1 of Kinetin were deep black-brown in colour, and had vivid, healthy chloroplasts in their all cells. On the contrary, the fronds cultured in other media were discoloured to light black-brown or green-drown, and almost all cells were vacuolated or shrunk gradually into death.(3) There was an obvious difference between the best growth-rates of the fronds cultured at 5.0mg/l of Kinetin at $5^{\circ}C$ and those at $10^{\circ}C$. The former was $366.7\%$, the latter $318.8\%$ but the difference was little at lower concentrations. (4) Many abnormal cells grown up to $25.0-27.5\mu$ in diameter were found among the marginal cells of fronds which showed the best growth in Kinetin, and the fronds wire $41.0-42.0\mu$ in thickness which was thicker by $10.0\mu$ or so than the others. (5) In two fronds at 1.0mg/1 of Kinetin cell-divisions were observed, which might developed into antheridium, but it was doubtful whether due to the efficiency of Kinetin.

• Parasites, Hosts and Diseases
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• v.28 no.3
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• pp.183-194
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• 1990

In an attempt to develop prophylactic and therapeutic measures of the intestinal giant-cystic disease caused by Thelohanellus kitauei in the Israel carp, Cyprinus carpio nodus, pathological observations were conducted upon the carps which were hatched in May 1988 and raised in a net cage fish farm at the Soyang lake, managed by Horim Fisheries for the period of 21 months with 1~2 months interval. After a gross inspection of the carps, necropsy was carried out periodically in order to clarify the pathological changes in various internal organs and muscular tissues. Also. the prevalence of the disease was checked during the period from 1988 to 1990. Gross inspections revealed that the infected carps showed some degree of fading in body and gill color, back-emaciation symptoms, reddish anus accompanying erosion and relaxation and pot-belly, as well as discharge of yellowish white mucoid material from the anus. However, most carps died eventually of intestinal obstruction. Other significant necropsy fadings included cyst formation of various size in the intestinal mucosa, ascites, anemic condition through internal organs and muscular tissues, hyperemia and dilation of intestines with decreased tension, thinness and fragility, and full contents of semi-fluid or yellowish white mucoid material in the intestinal canals. Based on the morphological characteristics of the spores found in the cysts, parasitic location in the intestines, macro- and microscopic findings of the lesions, the parasites were identised as Thelohanellus kitauei Egusa os Nakajima, 1981. Although monthly changes of water temperature were distinct, the extrusion rates of the polar filaments of the spores stayed constant throughout the year with an exception of a lower rate in July, The lesions initiated from mucosa and submucosa in early July became large swellings and then complete mature (orms following the peracute course. From late August the upper cysts were gradually opened and most of the spores were dispersed from anus into the surrounding water through December but only a few lasted until next April. The cysts were completely recovered until next September. Comparing the incidence and prevalence of the disease by year tremendous infection and death rates were checked in the first prevalent year, 1988, but the rates were significantly decreased in the second year, and showed an almost normal status in the third year, 1990. As the above summarized results showed, the disease entity might come to an end in three years after the first prevalent year, however, the spores must be strictly prevented because they could be infective in the water for one year.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.15-21
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• 1993

Crude ${\beta}-glucan$ extracted from Barley was purified by stepwise enzyme treatment (Thermostable ${\alpha}-amylase$, amyloglucosidase, protease). The Intrinsic Viscosity $[{\eta}]$ of the purified ${\beta}-glucan$ was determined by Cannon Fenske Capillary Viscometer (size 50, Cannon Instruments, State, College pa.) at different pH (2, 4, 7, 9, 11) and various salt concentration (0.01 M, 0.03 M, 0.05 M, 0.07 M, 0.1 M and 0.2 M). The $[{\eta}]$ of purified ${\beta}-glucan$ was ranged from $0.997{\sim}2.290\;dl/g$. The $[{\eta}]$ of purified ${\beta}-glucan$ at both alkali, acid condition were lower than those at pH 7. However, the alkali condition of puified ${\beta}-glucan$ solution showed less $[{\eta}]$ than the acid condition of this solution. From 0 M to 0.2 M salt concentration, the $[{\eta}]$ of purified ${\beta}-glucan$ solution was decreased to 0.03 M then increased to 0.05 M NaCl and remained constant to 0.2 M NaCl. The chain stiffness parameter of purified ${\beta}-glucan$ was not affected by temperature from $15^{\circ}C$ to $65^{\circ}C$. The shear rates of various ${\beta}-glucan$ conditions were determined by Bohlin Rheometer (Lund, Sweden). The ${\beta}-glucan$ concentration of 1.0 g/dl and 2.0 g/dl behaved as Newtonian fluid. However, above the concentration of 3.0 g/dl ${\beta}-glucan$ solution, it showed thixotropic and psedoplastic characteristics. Barley ${\beta}-glucan$ appears a damping at 0.5 frequency for the 4.0 g/dl solution. Below 0.5 frequency, it appears a viscous behavior property and above 0.5 frequency, it appears a elastic behavior property.