• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.441-453
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• 2017

This paper described the spatio-temporal distributions in the phytoplankton community, such as species composition, standing crops, and dominant species, from July 2012 to April 2013 in the Coastal Waters of Central South Sea (CWoCSS) of Korea. A total of 87 species of phytoplankton belonging to 52 genera were identified. In particular, diatoms and phytoflagellates comprised more than 62.1% and 37.9% of the total species, respectively. The phytoplankton cell density fluctuated with an annual mean of $7.9{\times}10^4cells{\cdot}L^{-1}$ between the lowest value of $1.0{\times}10^3cells{\cdot}L^{-1}$ in spring and the highest value of $4.5{\times}10^5cells{\cdot}L^{-1}$ in winter. The seasonal succession of the dominant species were Chaetoceros curvisetus, Ch. debilis in summer, Eucampia zodiacus in autumn, E. zodiacus, Thalassiosira curviseriata in winter and Skeletonema costatum -ls (like species), Leptocylindrus danicus in spring. According to principal component analysis, the phytoplankton community of the CWoCSS was characterized by the mixing rate between the freshwater inflow from Somjin River and the seawater of the South Sea, Korea.

• Journal of Nutrition and Health
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• v.40 no.1
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• pp.24-30
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• 2007

This study was designed to investigate the effects of pyroligneous liquor on lipid metaboilsm in serum of SPF/VAF Cri/Bgi CD rats. Male CD rats were fed basic diet prepared in our Lab., and PL-0 (control), PL-1, PL-25, PL-50, PL-75 groups were prepared with pyroligneous liquor (35% of Choa Co. Ltd.) of 0%, 1%, 25%, 50% and 75% in purified water per day for 8 weeks. Body weights and food intakes almost did not change in these five groups, and triglyceride (TG) levels were significantly decreased (20.5% and 19.5%, respectively) in these PL-25 and PL-50 groups compared with control group. Total and LDL-cholesterol levels were markedly decreased (20.7%, 16.3% and 20.3%, 116.9%, respectively) in these PL-25 and PL-50% groups, but HDL-cholesterol levels were significantly increased about 36.4% and 25.5% in serum of PL-25 and PL-50 groups compared with control group. Atherogenic indices were also remarkedly decreased (63.0%, and 50%, respectively) in these PL-25 and PL-50 groups compared with control group. These results suggest that long term administration orally of pyroligneous liquor in 25 to 50% may inhibit chronic degenerative disease through improving of lipid metabolism of lower TG & LDL-cholesterol and higher HDL-cholesterol, and lower AJ.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.245-251
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• 1998

A 10-week feeding experiment was conducted to determine the influence of several minerals from dietary mineral premix on growth and body composition in juvenile Korean rockfish. Three replicate groups of fish Initially averaging 4.2 g were fed one of the ten experimental diets. Korean rockfish muscle and casein as protein sources were used in the basal diet, and deleted one of each mineral (P, Ca, Zn, Mg, Fe, K, Mn, Se or all) in the control mineral premix, Weight gain, feed efficiency and nutrient retention in fish fed the diet not containing mineral premix were significantly lower than those in fish fed other diets (P<0.01). Weight gain in fish fed the diets deleted each mineral (P, Ca, Zn, Hg, Fe, K, Mn or Se) was lower than that of control diet (P<0.01), Feed efficiency and protein retention in fish fed the diets deleted each of P, Ca, Zn or Mn were lower than those ot control diet (P<0.01). Daily feed intake and lipid retention were not affected by dietary mineral premixes ( P>0.01). Proximate analysis and mineral contents in the whole body, muscle, liver or bone of fish fed the diets deleted each mineral were not different to control diet ( P>0.01). The data obtained in this study indicate that each of the P, Ca, Zn, Mg, Fe, K, Mn or Se is essential for normal growth of Korean rockfish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.290-294
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• 1999

An 18-week growth trial was conducted in flow-through aquarium system to investigate the effects of several additives in formulated diets on the growth and body composition of juvenile abalone (Haliotis discus hannai). Four replicate groups of abalone averaging 150 mg were fed one of four isonitrogenous ($33.8\%$) and isolipidic ($5.8\%$) diets containing $5\%$ squid meal, $0.5\%$ attractant, $1\%$ herb or $0.5\%$ lecithin. In addition, these formulated diets were compared to commercial diet. Survival rate and shell growth of abalone were not significantly affected by the different dietary additives and commercial diet (P>0.1). Body weight gain of abalone fed the diet containing herb was higher than those of abalone fed the diets containing squid meal or lecithin and commercial diet (P<0.1). Moisture, protein, lipid and ash contents of soft body were not influenced by dietary additives and commercial diet (P>0.1). The results suggest that herb as additive in this formulated diet can improve weight gain of abalone.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.284-289
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• 1999

A 15-week feeding trial was conducted to investigate the effect of formulated diet or macroalgae (Undaria pinnatifida) on the survival, growth and body composition of juvenile abalone (Haliotis discus hannai) under the different rearing environmental conditions (four shelter types and two water temperatures). Water temperature was maintained to $16.4^{\circ}C$ by heated and $13.7^{\circ}C$ by not heated natural sea water. The survival rate, weight gain and shell growth of abalone were affected by diet and water temperature (P<0.001). Survival rate of abalone fed the formulated diets was higher than that of abalone fed the Undaria pinnatifida at natural sea water (P<0.05), but this value was not influenced within abalone stocked at heated sea water in each shelter group (P>0.05). Weight and shell growth of abalone fed the formulated diets were significantly higher than those of abalone fed the Undaria pinnatifida at each temperature or shelter (P<0.05). Moisture, lipid and ash contents of the soft body were mainly affected by feeding diet than temperature or shelter (P<0.05). This study indicate that formulated diet used in this experiment could improve the growth of abalone independent of water temperature or shelter. and heated water could show a better growth of abalone in winter season.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.242-246
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• 2002

Growth and tetraspore release pattern of lithophyllum yessoense (Rhodophyta, Corallinaceae) were investigated from March 2000 to July 2001. Pinkish tetraspores were 40.2 $\pm$ 0.4 $\mu$m in diameter. After release, tetraspores attached on substrate shortly. Culture conditions were five temperatures (5, 10, 15, 20, 25^{\circ}C), four irradiances (0, 20, 50, 100 $\mu$mol${\cdot}m^{-2}$${\cdot}s^{-1}$) and six salinities (0, 9, 17, 25, 34, 43 ppt). Maximum growth of gametophyte was occurred at $20^{\circ}C$, $20{\mu}mol\;m^{-2}$${\cdot}s^{-1}$, 16: 8h (L:D) and 34 put. Maximum relative growth rate was 0.1232 at $20^{\circ}C$. The amount of tetraspore release showed maximum at September as 266 cells per crust area ($cm^2$), and tetraspores did not release from January to March.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.247-252
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• 2002

To prepare the edible film based on fish protein, the optimal conditions for extracting soluble protein from Alaska pollack ( Theragra chalcogramma) and mackerel (Scomber japonious) muscle were defined. The effects of protein concentration, pH and temperature of protein solution on the physical properties of films were also investigated, Contents of moisture, crude protein, crude lipid and ash in Alaska pollack muscle were 79.6, 18.2, 0.6 and $1.2\%$, respectively. Contents of moisture, crude protein, crude lipid and ash in mackerel muscle were 69,1, 20.1, 9,5 and $1.3\%$, respectively. Both soluble protein contents extracted from Alaska pollack and mackerel were the highest at pH 12.0, and then un 2.0, 11.0. But they were extracted a little at neutral range. forward the recovery yield of protein by controlling isoelectric point was the highest at pH 4.8 ($79.8\%$) for Alaska pollack and at pH 5.0 ($64.1\%$) for mackerel, For the preparation of protein films from both Alaska pollack and mackerel, the most effective conditions of film forming solution were achieved, after supplied fish protein 4 g (glycerol 1,6 g) in 100 mL of distilled water, by adjusted to pH 10.0 and then heated at $90^{\circ}C$.

• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.105-110
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• 2011

This study determined the effects of the dietary moisture level and feeding rate on the growth and gastric evacuation of young olive flounder. Four experimental diets with different moisture levels (9%, 21%, 30%, and 40%) were prepared through the addition of water to the commercial extruded pellet. Three replicate groups of fish (initial weight: $106{\pm}1.4\;g$) were fed diets containing 9%, 21%, 30%, and 40% moisture to satiation or a moisture level of 9% and 30% at a restricted feeding rate (95% of satiation) for 15 weeks. The mean water temperature was $22{\pm}1.6^{\circ}C$ during the feeding trial. Gastric evacuation rates were determined post-feeding. The dietary moisture levels did not significantly affect weight gain, but the weight of the fish receiving 9% and 30% moisture diets to 95% satiation were significantly lower than those of the fish fed 9-40% moisture diets to 100% satiation (P<0.05). The feed efficiency, protein efficiency ratio, viscerosomatic index, and survival were not significantly affected by the dietary moisture levels and feeding rates. The daily feed intake of the fish fed to 100% satiation did not significantly differ among the treatment groups. The stomach contents that peaked within 3 h of feeding gradually decreased, and the stomachs of fish were completely evacuated within 18 h. The contents of the intestine peaked at 3-12 h post-feeding, and then declined with the intestine being mostly evacuated at 30 h. The moisture of the stomach contents reached approximately 70% within 3 h post-feeding and gradually increased to approximately 75% within 12 h. No considerable differences were observed in the gastric evacuation and moisture levels of the stomach contents in the fish fed the different diets. The results of this study suggest that the gastric evacuation of olive flounder was not affected by the dietary moisture level and that the addition of water into the diet displayed no beneficial effects on the growth of young olive flounder.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1519-1528
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• 2013

Bacillus pumilus SG2, a halotolerant strain, expresses two major chitinases designated ChiS and ChiL that were induced by chitin and secreted into the supernatant. The present work aimed to obtain a mutant with higher chitinolytic activity through mutagenesis of Bacillus pumilus SG2 using a combination of UV irradiation and nitrous acid treatment. Following mutagenesis and screening on chitin agar and subsequent formation of halos, the mutated strains were examined for degradation of chitin under different conditions. A mutant designated AV2-9 was selected owing to its higher chitinase activity. To search for possible mutations in the whole operon including ChiS and ChiL, the entire chitinase operon, including the intergenic region, promoter, and two areas corresponding to the ChiS and ChiL ORF, was suquenced. Nucleotide sequence analysis of the complete chitinase operon from the SG2 and AV2-9 strains showed the presence of a mutation in the catalytic domain (GH18) of chitinase (ChiL). The results demonstrated that a single base change had occurred in the ChiL sequence in AV2-9. The wild-type chitinase, ChiL, and the mutant (designated ChiLm) were cloned, expressed, and purified in E. coli. Both enzymes showed similar profiles of activity at different ranges of pH, NaCl concentration, and temperature, but the mutant enzyme showed approximately 30% higher catalytic activity under all the conditions tested. The results obtained in this study showed that the thermal stability of chitinase increased in the mutant strain. Bioinformatics analysis was performed to predict changes in the stability of proteins caused by mutation.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1319-1330
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• 2000

Activated carbons prepared by chemical activation of organic waste sludges with $ZnCl_2$ and $K_2S$ have been studied in terms of their pore development and adsorptivity. Pore development of the carbons prepared from organic waste sludges was characterized by the nitrogen adsorption at 77K. The $ZnCl_2$-activated carbon produced by chemical activation with zinc chloride exhibited type I isotherm characteristics according to the BDDT classification, suggesting the presence of micropores formed by activation process. The isotherms of the commercial powdered activated carbon and $K_2S$-activated carbon reveal a hysteresis similar to that of type IV in BDDT classification, indicating the formation of mesopores. This result implies that the major pores of $K_2S$-activated carbon are composed of meso and micropores, and a macropores are minor. The adsorptive capacities of metal on the $K_2S$-activated carbon prepared from organic waste sludges were found to be superior to those on a commercial granular activated carbon. The Langmuir and Freundlich isotherms yield a fairly good fit to the adsorption data, indicating a monolayer adsorption of metals onto $K_2S$-activated carbon. The adsorptive capacity of the $K_2S$-activated carbon was superior to $ZnCl_2$-activated carbon for $PO_4$-P, and vice versa for $NO_3$-N. From the results of the studies reported here, it can be concluded that activated carbons with adsorptivity superior to commercial granular activated carbons can be produced from organic waste sludge using a two-step carbonization/activation procedure with zinc chloride or potassium sulfide as the activating agents.