• The Korean Journal of Ecology
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• 제22권6호
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• pp.337-342
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• 1999

Rotifer grazing rates in both species and community levels on bacteria and phytoplankton were determined by using representative models (fluorescent beads: 0.75$\mu m$ for bacteria and 10 $\mu m$ for phytoplankton) at biweekly intervals. One-year study at the lower part of the Nakdong River (Mulgum) indicated that the seasonal pattern of rotifer biomass was similar to that of total zooplankton biomass. Total mean biomass of rotifers was significantly higher than that of other groups (rotifers, 148$\pm $327 $\mu g$C/l; cladoceran. 25$\pm 69$$\mu g$C/l; copepodids. 58$\pm 159$$\mu g$C/l). For laboratory grazing experiments. mean specific filtering rate (SFR: $ml\cdot \; l^{-1}\cdot \; day^{-1}$) for rotifers varied from 0.001 to 0.726, and > 90% individuals of rotifer species took up fluorescent microspheres. The high SFRs were achieved by Brachionus angularis, B. calyciflorus, and Filinia longiseta. Community filtering rates (CFRs, $ml\cdot \; l^{-1}\cdot \; day^{-1}$) varied in the range from 2 ~ 1,670. Rotifer filtering rates on phytoplankton were much higher than bacterial filtering rates, especially in the late growing season (May. June, and November). Rotifers appear to be important in transferring both bacterial and phytoplankton carbon to higher trophic levels at the lower Nakdong River.

• 한국환경과학회지
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• 제12권8호
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• pp.847-852
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• 2003

It was examined carefully that the bacterial die-off between Chlorella vulgaris and E. coli. W3110 was tested through adding TOC (total organic carbon) with the lab-scaled continuous river water flow system (CRWFS). Artificial synthetic wastewater was applied at two levels of organic carbon concentration; 1,335 mg/l in treatment type 1 and 267 mg/l in type 2. In both types, the population densities of Chlorella vulgaris were similar in a maximum 8.25 ${\times}$ 10$\^$6/ cells/ml (type 1) and 6.925 ${\times}$ 10$\^$6/ cells/ml (type 2). The maximum densities of E. coli. W3110 were 2.0 ${\times}$ 10$\^$8/ colony forming unit (CFU)/ml in type 1 and 3.9 ${\times}$ 10$\^$8/ CFU/ml in type 2. The densities increased for 11 days in type 1 and 4 days in type 2, then decreased rapidly till the 35th day, then slightly increased again. This trend was prominent in type 2. It implied that a wider range of nutrients was required in the growth of heterotrophic bacteria in type 2 than in type 1. We could not expect successful bacterial die-off if the wastewater retention time was not furnished sufficiently.

• ALGAE
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• 제17권3호
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• pp.195-199
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• 2002

We investigated the association of Chlorella vulgaris and E. coli W9110 in removal of total organic carbon with the lab-scaled continuous river water flow system (CRWFS). Artificial wastewater was applied at two levels of organic carbon concentration; 1,335 $mg{\cdot}l^{-1}$ in the treatment (T)-1 and 267 $mg{\cdot}l^{-1}$ in T-2. The highest densities of C. vulgaris were $8.3{\times10^6\;cells{\cdot}ml^{-1}$ in T-1 and $6.9{\times}10^6\;cells{\cdot}ml^{-1}$ in T-2. The maximum densities of E. coli W3110 were $2.0{\times}10^8$ clony forming unit (CFU)${\cdot}ml^{-1}$ in T-1 and $3.9{\times}10^8\;CFU{\cdot}ml^{-1}$ in T-2. The densities increased during the first 11 days in T-q and 4 days in T-2, and decreased rapidly till 35th day, then increased slightly afterwards. This trend was prominent in T-2. It was inplied that wider range of nutrients was required in the growth of heterotrophic bacteria in T-2 than in T-1. The algal biomass should be increased effectively for the successful removal of organic carbon.

• 대한수의학회지
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• 제42권3호
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• pp.327-333
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• 2002

The study was carried out to examine the distribution and survival rate of Listeria monocytogenes (L monocytogenes) from various source of waters using improved isolation method. In comparision of enrichment media for isolation of L monocytogenes from water, the isolation rate and 50% detection limit of the pathogen were higher in UVM modified Listeria enrichment broth (UVM) than Listeria enrichment broth (LEB). On the other hand, when compared the selective media for isolation of the pathogen from water, the isolation rate was highest in culture at Oxford agar followed by Fraser agar, and LEB agar. In order to improve enrichment method, 100 ml of water samples with 0.1 CFU/ml of L monocytogenes was inoculated into 10 ml of UVM concentrated at 10-fold, and incubated for 24 h at $36^{\circ}C$. Isolated frequency of the pathogens in improved enrichment method completely corresponded with common (filter) method. Of a total mumber of 147 water samples from river, lake and sea, the pathogen was isolated from 1 of 39 (2.6%) river water samples and 1 of 75 (1.3%) sea water samples, but no pathogen was isolated from 33 lake water samples. Serotypes of 2 isolates were identified as type 1. L monocytogenes decreased in number from 7.2-7.4 to 4.2-4.7 log CFU/ml for 1 week poststorage (5 and $20^{\circ}C$), but the pathogens were able to be detected in river and sea water until 8 weeks after storage. However, in tap water, L monocytogenes were decreased to undetectable level after 2 weeks of storage.

• 미생물학회지
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• 제32권3호
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• pp.238-244
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• 1994

부영양화된 낙동강 하구역에서 세균에 의한 용존 유기물의 이용능을 조사하고 이에 미치는 환경요인의 영향을 파악하기 위하여 미생물학적 요인과 물리화학적 환경요인의 연중 변화를 분석하였다. 총세균수는 0.33 ~ $2.09{\times}10^7$ cells/ml의 변화폭을 나타냈으며, 오염부하량이 큰 정점에서 종속영양세균의 개체수와 비례하였다. 세균이 체적과 생물량은 각각 0.064~0.156 ${\mu}m^3$/cell, 0.163~1.036 ${\mu}g$-C/ml을 나타냈다. 세균의 이차생산성은 0.24~60.86 ${\mu}g$-C/l/h의 범위로 측정되었으며, 부영양화 지표로 사용되는 환경인자와 밀접한 관계를 보였다. 담수역에 속하는 정점에서의 세균생산성의 계절별 변화는 동계에 최고치를, 하계에 최저치를 나타내어 갈수기의 오염부하량 증가와 밀접한 상관성을 보였다. 해수역에 속하는 다대의 경우 동계에 낮은 값을, 하계에 높은 값을 나타내고, 환경요인 중 엽록소 a, 수은 등과 밀접한 상관성을 보였다 (r>0.5, p<0.05). 이로 미루어 낙동강 하구의 하구언 상류역에서는 주위에서 유입되는 유기물이, 하구언 하류역에서는 식물성 플랑크톤의 광합성 산무링 세균의 이차생산성에 미치는 주 영양물질임을 암시하고 있다.

• 한국환경보건학회지
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• 제34권4호
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• pp.292-299
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• 2008

The purpose of this study was to investigate the teratological effects of enrofloxacin, a veterinary antibiotic, on the embryos and fetus of hatching chicken eggs. A control group and four experimental fertilized egg groups were set up. The four experimental groups were injected with 0.05 ml, 0.1 ml, 0.2 ml, and 0.3 ml enrofloxacin ($50{\mu}g/ml$) respectively. During the hatching period, the weights of total eggs, inside material(yolk and white) and embryos or fetuses, embryo growth, and teratological effects were investigated. In the experimental groups (fertilized eggs injected with 0.05 ml, 0.1 ml, 0.2 ml and 0.3 ml enrofloxacin), the weights of total eggs were decreased, but the yolk and white weights were increased by the higher amount of antibiotics. The weights of embryos (fetuses) in experimental groups were 86.1%, 78.6%, 65.6% and 61.4% of the control, respectively. Retarded growth, deformity and embryo loss were observed in experimental groups. Teratological effects such as undeveloped eyes, wings and legs, and deformed head and bill were also detected. In conclusion, we found that veterinary antibiotics, enrofloxacin have made teratological effects on the embryos and fetus of hatching eggs.

• 한국미생물·생명공학회지
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• 제28권4호
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• pp.202-208
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• 2000

Four bacteria capable of using aniline as a sole source of carbon and energy we4e isolated from river waters. Among them, two strains were identified as Stenotrophomonas maltophilia based on their physiological and biochemical characteristics and 16SrRNA gene sequence and the others as delftia acidovorans. The four strains were able to grow on the mineral salt media containing aniline at concentrations up to 6,000 $\mu\textrm{g}$/ml. Since aniline degradation by S. maltophilia has not been reported so far, the two strains A-s and 51-4 were selected for further studies. They completely utilized aniline in a mineral salt medium containing 300 $\mu\textrm{g}$/ml of aniline as a sole carbon and energy source within 24 hours. Optimum pH and temperature for aniline degradation and cell growth of both strains were 7.0 and $35^{\circ}C$, respectively. In addition, they effectively degraded aniline is waste, underground and river waters containing 300 $\mu\textrm{g}$/ml of aniline. This is the first report of aniline degradation by S. maltophilia strains.

• 한국환경보건학회지
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• 제16권2호
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• pp.47-53
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• 1990

This experiment was carried out to evaluate general characteristics of the water quality, total coliform, fecal coliform and microflora at the St. 1 to St. 3 and St. 4 to St. 7. Eighty-four water samples were collected from the 7 stations from July 1988 to April 1990 (see Fig. 1) Range and mean value of the samples were as follows water temperature 2.0-29.9$^{\circ}$C, 16.3$^{\circ}$C pH 6.86-9.08, 7.62: electrical conductivity 54.85$\mu \mho$/cm, 4.300 m$\mho$/cm, 911.93 $\mu \mho$/cm : turbidity 0.9-36 NTU, 6.8 NTU, respectively. pH and electrical conductivity at St. 4 to St. 7 were higher than those at St. 1 to St. 3, but turbidity at St. 1 to St. 2 was 7 times higher than that at Sonagdong river area. The bacterial density of the samples ranged 91-110,000/100ml for total coliform. 21-15,000/100ml for fecal coliform. Specially, the geometric mean value of the St. 3 was 11,836 / 100ml for it leveled heavy contaminaiton. Predominant species among the 3,874 strains isolated form the samples were 30.6% Enterobacteriaceae, 14.7% Acinetobacter, 9.0% Aeromonas. 8.9% Neisseria, and 7.5% Vibrio.

• 한국수산과학회지
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• 제32권3호
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• pp.243-246
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• 1999

황복 (Takifugu obscurus)의 정자보존을 위한 기초자료를 얻고자, 정액의 특성을 파악하고 정자의 냉장보존 조건에 관한 연구를 수행하였다. 정액의 ml당 정자수는 $1.13\pm0.34\times10^{10}/ml$이었고 spermatocrit는 64.8$\pm$1.4였으며, 정장의 삼투질농도는 266$\pm$2 mOsm/kg이었다. 총 단백질 함량과 총 지질 함량은 정장에 비해 정자에서 높았으며, glucose는 검출되지 않았다. $Ca^{2+}$과 $Na^{+}$ 농도는 정자에 비해 정장에서 높았고, $Mg^{2+}$과 $K^{+}$은 정장에 비해 정자에서 높은 값을 보였다. 황복 정자를 여러 가지 희석액을 이용하여 16 일간 $0\pm0.5^{\circ}C$에서 냉장보존 하였을 때, 수정률은 $0\~0.7\%$로 보존 효과가 저조한 것으로 나타났다.

• 환경위생공학
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• 제10권2호
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• pp.36-45
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• 1995

Physicochemical environments and phytoplankton community in the nakdong river middle basin were investigated during a period of 1 year from Nov. 1993 to Oct. 1994. The ranges of Physicochemical environment factors in the nakdong river middle basin were $3.6~27.4{\circ}C$ for temperature, 7.1~9.3 for pH, $7.1~12.7mg/{\ell}$for DO, $0.7~2.1mg/{\ell}$ for BOD, $31~52mg/{\ell}$ for alkalinity, $2.101~3.3mg/{\ell}$ for T-N, $0.052~0.099mg/{\ell}$ for T-p, $5.4~92.3mg/m^{3}$ for chlorophyll-a. The number of Phytoplankton was lowest in Jan. that is, 244ce11s/ml and that was highest in Sep. 1201 cells/ml. The increase of dominant genera were correlated with the total nomber of phytoplanktons. Bacillariaceae, chlorophyceae, cyanophyceae, and euglenophlrceae were to 74.5%, 20%, 3.5%, and 2.2% respectively. Bacillariaceae were abundant during all the year round except for Jun, Jul, Aug. Chlorophyceae were plentiful in Jun, Jul, Aug. Tase-and odor-causing algae and filter clogging algae were 72% in Nov. and 93.5% in Jun. They were abundant all the year round except for winter, so they influenced on the treatment of tap water system. They belong to the general asterionella, cyclotella, melosira, nitzschia of bacillariaceae and actinastrum, pediastrum of chlorophyceae. Dominace index was low in winter and high in umber. Diversity index and equitability index were low in summer and high in winter. Therefore, the structure of phytoplankton community of the nakdong river middle basin was different form season to season.