• KSBB Journal
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• v.11 no.1
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• pp.92-98
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• 1996

A chitinase-producing bacterium was isolated from seashore mud around Beobseongpo in Chunnam province by selective enrichment culture, and among it, one isolate which was the best in producing of chitinase was selected. Nutrient or MacConkey medium was confirmed with secreting of prodigiosin pigment by Serratia sp. JM, and it was performed by the production of clear zone on medium containing chitin. Serratia sp. JM was almost same compared with Serratia marcescens ATCC 27117 in respect of its morphological, physiological and biochemical characteristics except succinic, urea and pyruvic acid. Serratia sp. JM was resistant to tetracycline but was not resistant to kanamycin and chloramphenicol. The optimal temperature and pH for the production of chitinase from Serratia sp. JM were $30^{\circ}C$ and 7.5, respectively. Production of chitinase and pH in the medium increased until the cultivation of 120 hours, but after 120 hours, they were decreased due to the acetic acid accumulated from degradation of chitin by Serratia sp. JM.

• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.36-46
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• 2004

We evaluated the effect of limiting nutrients and N/P ratio on the growth of phytoplankton in a small eutrophic reservoir from November 2002 to December 2003. Nutrient limitation was investigated seasonally using nutrient enrichment bioassay (NEB). DIN/DTP and TN/TP ratio (by weight) of the reservoir during the study period ranged 17${\sim}$187 and 13${\sim}$60, respectively. Most of nitrogen in the reservoir account for $NO_3$-N, but sharp increase of ammonia was evident during the spring season. Seasonal variation of dissolved inorganic phosphorus concentration was relatively small. DTP ranged 26.5${\sim}$10.1 ${\mu}g\;P\;L^{-1}$, and the highest and lowest concentration was observed in August and December, respectively. Chlorophyll a concentration ranged 28.8${\sim}$109.7 ${\mu}g\;L^{-1}$, and its temporal variation was similar to that of cell density of phytoplankton. Dominant phytoplankton species were Bacillariphyceae (Melosira varians) and Chlorophyceae (Dictyosphaerium puchellum) in Spring (March${\sim}$April). Cyanophyceae, such as Osillatoria spp., Microcystis spp., Aphanizomenon sp. dominated from May to the freezing time. TN/TP ratio ranged from 46 to 13 (Avg. 27${\pm}$6) from June to December when cyanobacteria (Microcystis spp.) dominated. p limitation for algal growth measured in all NEB experiments (17cases), while N limitation occurred in 8 out of 17 cases. The growth rates of phytoplankton slightly increased with decreasing of DIN/DTP ratio. Evident increase was observed in the N/P ratio of > 30, and it was sustained with DTP increase until 50 ${\mu}g\;P\;L^{-1}$. Under the same N/P mass ratio with the different N concentrations (0.07, 0.7and 3.5 mg N $L^{-1}$), Microcystis spp. showed the highest growth rate in the N/P ratio of< 1 with nitrogen concentration of 3.5 mg N $L^{-1}$). The responses of phytoplankton growth to phosphate addition were clearly greater with increase of N concentration. These results indicate that the higher nitrogen concentration in the water likely induce the stronger P-limitation on the phytoplankton growth, while nitrogen deficiency is not likely the case of nutrient limitation.

• Korean Journal of Environmental Biology
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• v.24 no.3
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• pp.230-239
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• 2006

Nutrient over-enrichment as a consequence of anthropogenic loading leads to eutrophication, which has the detrimental effects on river and stream ecosystems. To examine dynamics of factors causing cultural eutrophication in a over-licked mountain stream due to anthropogenic loading, physicochemical parameters were measured from 5 stations in the upper Daecheon stream, Busan, from January 2002 to May 2003. The five study sites were located along the stream gradient. DC1 is upper most clean site, and DC5 is located at the lowest area. Wastewater was released into the stream from just upstream of DC2 site. Water column ammonium and phosphate concentrations were higher during winter than other seasons, while water column nitrate +nitrite concentration did not show clear seasonal variation. Water column ammonium, nitrate+nitrite and phosphate concentrations were lowest at DC1 and highest at DC2 in which waste water loading occurred. TOC and DOC, conductivity, turbidity, and BOD in the water column were also increased drastically at DC2, and then decreased at DC5. Sediment pore water phosphate concentrations during winter and spring were higher than those in summer and fall, while sediment pore water ammonium and nitrate +nitrite concentrations showed no seasonal trend. Sediment pore water ammonium and phosphate concentration were also increased at DC2 and slightly decreased at DC5, while sediment pore water nitrate+nitrite concentration was highest at DC5. Organic matter and inorganic nutrients at up-stream of Daechon stream significantly increased as a result of wastewater discharge, and the nutrient concentrations decreased at low-stream suggesting self-purification ability of the stream.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.503-510
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• 2007

The purposes of the study were to analyze the seasonal effects on the fish fauna and compositions including trophic guilds and tolerance guilds. For the study, we collected fish samples twice in June as premonsoon period and early September 2007 as monsoon periods in five sampling sites of the Gap Stream, and then biological oxygen demand (BOD), nutrients (TN, TP) and suspended solids (SS) were compared with the guild data along the gradient of upstream-to-downstream. Chemical water quality, based on BOD, TP, and TN degraded gradually from the upstream to downstream reach and there were about 3 fold difference between S1 and S5. Water quality was worse in the premonsoon than the monsoon, and the heavy monsoon resulted in a dilution of the polluted river by rain water, especially, in the downstream reach. Total number of fish species, based on the catch per unit effort (CPUE), showed a distinct difference between the two seasons; 30 species were sampled in premonsoon, but 23 species were sampled in the monsoon, indicating a seasonal difference in the fish fauna. Tolerant species dominated the fish community (48.3%) in the stream, and the proportions prior to physical disturbance by the monsoon rain were evidently greater in the downstream reach than the upstream. This reflected the characteristics of urban stream polluted by nutrient enrichment as shown in the BOD and TP values. Sensitive species in the premonsoon decreased from the gradient of upstream-to-downstream reach. Such seasonal modifications in the trophic and tolerance guilds were evident. In the analysis of trophic guild and habitat guild, during the premonsoon the proportion of insectivore and riffle-benthic species were largely greater in the upstream reach than the downstream, whereas the proportions were opposite along the gradient of the stream in monsoon. Thus, the patterns of chemical water quality along the longitudinal gradients reflected the premonsoon conditions of insectivores and tolerant species, indicating that summer monsoon data of fish may not match with water quality due to large physical disturbance by flow regime. Seasonal monsoon in this region as well as the chemical pollution may act as a key role influencing the fish compositions of trophic and tolerance guilds and fauna. The data collected during the premonsoon rather than the monsoon, thus, may be better predictor for a diagnosis of stream health conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1622-1633
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• 2002

The effects of tuna oil supplementation (0, 1, 2 and 3%) to pig diets on growth and carcass yield as well as meat quality were determined in 40 crossbred pigs. Animals were fattened from 30 to 90 kg of live-weight. Twenty-four hours after slaughter, following various early- and late-post mortem measurements, loin, backfat and belly were prepared from the carcasses. Bacon was produced from the belly part by curing and smoking. Neither performance (feed intake, daily gains, feed conversion efficiency) nor carcass quality (slaughter weight, dressing percentage, lean percentage, nutrient composition of the loin) were significantly affected by tuna oil supplementation. Tuna oil also had no clear effects on early- and late-post mortem meat quality traits, water-holding capacity and tenderness of the M. longissiumus dorsi (LD). Colour traits of LD and backfat, and backfat firmness were not significantly affected by tuna oil, either. However, there was a certain trend to elevated fat contents of LD (and bacon), but not of backfat, with increasing levels of tuna oil in feed. Pigs receiving elevated proportions of tuna oil expressed lower VLDL cholesterol and triglyceride concentrations in blood plasma, whereas the cholesterol content of LD, backfat and bacon did not reflect this trend. Effects of tuna oil on fatty acids in LD, backfat and bacon were often small in extent, except those concerning the long-chain polyunsaturated fatty acids. With 3% tuna oil in the diet, the contents of the particularly desired omega-3 fatty acids, C20:5 and C22:6, were 0.1 and 0.2 g/kg in LD. The corresponding values for backfat and bacon were 2.6 and 12.6 g/kg, and 1.3 and 9.2 g/kg, respectively. Tuna oil supplementation was associated with significant adverse effects on flavour and overall acceptance of bacon (not significant in LD although numerically the same trend was noted), but these effects on sensory ratings were limited in extent. Also shelf life of the products, determined as TBA value after different storage periods at $4^{\circ}C$ in LD, backfat and bacon, was significantly reduced. Overall, the present study suggests that omega-3 fatty acids may be enriched in pork by feeding tuna oil with few undesired side-effects, particularly those on sensory perception and shelf life, suggesting immediate consumption of the products is advisable. Most economically important traits (performance, slaughter and physical meat quality) remained unaffected.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.313-319
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• 2004

The distribution and characteristics of acidotolerant heterotrophic and naphthalene-degrading bacteria were investigated in two forest areas, one near Ulsan petrochemical industrial complex (Sunam) and the other in countryside (Daeam). Average values of soil pH at Sunam and Daeam were 3.8 and 4.6, respectively. When het­erotrophic and naphthalene-degrading bacteria were enumerated by most probable number (MPN) procedures at Sunam, the median values of heterotrophs growing at pH 7.0 and pH 4.0 were $5.3{\times}10^7\;and\;3.3{times}10^7$ MPN/g, whereas those of naphthalene-degraders were $5.6{\times}10^4\;and\;4.0{times}10^5$ MPN/g, respectively. While the medians of heterotrophs at Daeam were larger than those at Sunam, the concentrations of naphthalene-degraders were higher at Sunam compared to those at Daeam. From the MPN tubes and enrichment cultures, we obtained 17 isolates of naphthalene-degraders which were identified as Sphingomonas paucimobilis, Brevundimonas vesic­ularis, Burkholderia cepacia, Ralstonia pickettii, Pseudomanas fluorescens, and Chryseomonas luteola. Among them, 6 isolates showed higher naphthalene-degrading activity on minimal media of pH 4 compared to pH 7, whereas the extent of growth was not greater at pH 4 than at pH 7 when they were inoculated on nutrient-rich media. It is plausible that the pH may affect naphthalene-degrading activity of the isolates by changing fatty acid composition of bacterial membrane.

• Journal of Life Science
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• v.7 no.1
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• pp.30-38
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• 1997

For screening thermostable $\alpha$-amylase from thermophiles, various samples from extreme environments such as hot spring and sewage near them, and compoat, wereexamined microbial growth in enrichment culture medium at 55$\circ$C on the assumption that enzymes from thermophiles are inevitable thermostable. One strain showing higher $\alpha$-amylase activity was pure cultured and designated as Bacillus sp. TR-25 from the results of morphological, cultural and physiological characteristics. The most important carbon sourses for the enzyme production were soluble starch, dextrin, potato starch and corn starch. Glucose and fructose had a catabolite repression on the enzyme production. The good nitrogen sources for the enzyme production were yeat extract, nutrient broth, tryptone, corn steep liquor and ammonium sulfate. The enzyme production was accelerated by addition of CaCl$_{2}$. $\cdot $ H$_{2}$O. The optimal medium composition for the enzyme production was soluble starch 2.0%, yeast extract 0.55, CaCl$_{2}$ $\cdot $ 2H$_{2}$O 0.015, Tween 80 0.001%, pH8.0, respectively. In jar fermenter culture, this strain shows a rapid growth and required cheaper carbon and nitrogen source. These properties are very useful to fermentation industry. The $\alpha$-amylase of this strain demonstrated a maximum activity at 80$\circ$C, pH 5.0, respectively. And calcium ion did not improve thermostability of the enzyme. At 10$0^{\circ}C$, this enzyme has 235 of relative activity. Transformation was carried out by thermophilic Bacillus sp. TR-25 genomic DNA. As a result, the transformant has increased thermostable $\alpha$-amylase activity.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.1 s.28
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• pp.1-7
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• 2007

In order to develop the deep ocean water, the characteristics of vertical distribution of dissolved trace metals(Cd, Co, Cu, Ni, Pb, Zn) were investigated from Apr. to Oct., 2005 in the East Sea. Total six sampling sites were selected in Gangwon-Do and Gyeongsangbuk-Do. Accuracy of the analytical procedures was assessed by the SRM(CASS-4) for dissolved metals in seawater. The mean recoveries cf CASS-4 ranged from 89.4% for Co to 99.8% for Cd. In this study, the dissolved metal concentrations varied with space, time and element. The metal concentrations showed wide range in the surface. Cd, Ni and Zn showed a nutrient-type profile with surface depletion and enrichment at depths. However, Co, Cu and Pb were irregular in the vertical distribution. All metal concentrations studied in this study are lower than the criteria cf Korean drinking water.

• 한국해양학회지
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• v.29 no.2
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• pp.107-118
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• 1994

An investigation of the annual change and C:N:P ratio in particulate organic matter (POM) in Chinhae Bay, a semi-enclosed bay of the southern coast of Korean Peninsula, was carried out for a period of 12 months between January and December, 1993. The concentrations of POM have a broad range: 198∼4,416 ugC/l, 24∼792 ugN/l and 4.5∼69.0 ugP/l, Marked seasonal changes of POM, particularly particulate organic carbon (POC) and nitrogen (PON), were observed in the surface water. Generally, the concentration of POM peaks in summer. The C:N:P composition ratio of particulate organic matter, which is high in summer, also shows a seasonal change. The C:N assimilation ratio is constant at 6.53, which is consistent with the Redfield ratio. The significant linear relationship between POM and chlorophyll-a in the surface water during the survey period (except for January and February) and the C:N ratio suggest that the concentration of POM is controlled by phytoplankton biomass. POM peaks in summer, a period characterized by high freshwater input and the strong stratification, as a result of the intense proliferation of phytoplankton by a large amount of nutrient loading from the tributaries. On the other hand, the high C:P and N:P ratios in summer indicate that P is limited for phytoplankton growth owing to N-enrichment from a high input of freshwater with a high dissolved inorganic N:P ratio.

• 한국해양학회지
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• v.26 no.3
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• pp.204-222
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• 1991

The annual cycles of plant major nutrients and dissolved oxygen in a nutrients-rich semi-enclosed coastal inlet, chinhae Bay, of the southern coast of the Korean Peninsula are first presented. The water column of the bay is stratified during summer (April-late September) and well0mixed during winter (October-March). During the summer stratification period, dissolved oxygen contents exceed 400uM in the surface but diminish to less than 50uM in the near bottom waters, which often results in an anoxic environment in the inner part of Chinhae Bay. After the breakdown of the stratification in October, dissolved oxygen concentration remains undersaturated until February. The evidence of allochthonous input of N-nutrients throughout the year is readily seen in the water column: however. crude budget calculations show that the nutrients are efficiently utilized within the bay ecosystem, and that export of the nutrients from the bay to the shelf must be negligible. There is no sign of the enrichment of the nutrients in the water column. The eutrophication phenomenon sensu stricto is not observed in chinhae Bay. Using the standing stock of dissolved oxygen and estimation of the oxygen fluxes across the air-sea boundary, a benthic oxygen respiration rate during winter is estimated conservatively at 21-24 mmol Cm/SUP -2/d/SUP -1/. this oxygen respiration rate accounts for about 20% of the total phytoplankton production in winter.