• 한국물환경학회지
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• 제34권4호
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• pp.375-381
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• 2018

The monitoring of phytoplankton biomass and community structure is essential as a first step to control the harmful cyanobacterial blooms in freshwater systems, such as seen in rivers and lakes, due to the process of eutrophication and climate change. In order to quantify the biomass of phytoplankton with a wide range in size and shape, the measurement of cell biovolume along with cell density is required for a comprehensive review on this issue. However, most routine monitoring programs preserve the gathered phytoplankton samples before analysis using chemical additives, because of the constraint of time and the number of samples. The purpose of this study was to investigate the cell biovolume change characteristics of six cyanobacterial species, which are common bloom-causing cyanobacteria in the Nakdong River, after the preservation with Lugol's iodine solution. All species showed a statistically significant difference after the addition of Lugol's iodine solution compared to the live cell biovolume, and the cell biovolume decreased to the level of 34.0 ~ 56.3 % at maximum in each species after the preservation. The nonlinear regression models for determining the shrinkage ratio by a preservation period were derived by using the cell biovolume measured until 180 days preservation of each target species, and the equation to convert the cell biovolume measured after preservation for a certain period to the cell biovolume of viable cell was derived using that formula. The conversion equation derived from this study can be used to estimate the actual cell biovolume in the natural environment at the time of sampling, by using the measured biovolume after the preservation in the phytoplankton monitoring. Moreover this is expected to contribute to the final interpretation of the water quality and aquatic ecosystem impacts due to the cyanobacterial blooms.

• 한국물환경학회지
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• 제34권2호
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• pp.210-215
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• 2018

It is difficult to count colonial cyanobacteria Microcystis cells since the thickness of colonies is constrained by amorphous mucilage, making it impossible to estimate the number of cells. Disaggregation of Microcystis colonies into single cell is needed to improve the accuracy and precision of cell density estimation of naturally collected samples. Uultrasonic treatment method is commonly used owing to the simplicity and immediacy of the procedure. However, amplitude, frequency, and duration of ultrasonic treatment also cause cell loss during the experiment. Optimal ultrasonic treatment has not been standardized yet. Therefore, the objective of this study was to investigate optimal ultrasonic treatment by analyzing cell density and colony numbers. We collected colonial Microcystis from Changnyeong-Haman weir area in Nakdong River during harmful algal boom period from September to October in 2017. Ultrasonic treatment method was applied to disrupt colonies into single cells to enumerate cell density. Among treatment conditions, results from continuously treated for 100 seconds were found to be the optimum to reduce colonies to a suspension of single cell without cell losses under high and low density of Microcystis cells. Lugol iodine fixed cells followed by sonication showed less negative impact of cell damage within the optimal treatment time (100 seconds). Furthermore, disaggregated cells treated by sonication enables microscopic observation more easily since gas vacuoles were collapsed to facilitate sedimentation of cells under the counting chamber for quantitative enumeration of buoyant Microcystis cells.

• 한국양식학회지
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• 제10권3호
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• pp.227-237
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• 1997

Five species of intertidal clams including Ruditapes philippinarum, Tegillarca granosa, Solen strictus, Heteromacoma irus, and Coecella chinensis were tested for the presence of the protozoan parasite, Perkinsus sp. using fluid thioglycollate medium (FTM) fortified with antibiotics and histological techniques. Each individual clam was placed in a test tube filled with 10ml FTM, placed in totally dark place, and incubated over a week. After incubation the clam tissues were stained with Lugol's iodine solution and examined under a light microscope to find out any hypnospores of Perkensus sp. in the tissues. Cross-sections of the clams were also embedded in paraffin, sliced to 3um, and stained with Harry's hematoxylene and Picro eosine to observe the presence of tomont or trophozoites. Perkinsus sp. were found in the presence of tomont or trophozoites. Perkinsus sp. were found in the tissues of R. philippinarum collected from Kangjin and Wando, along the south coast of Korea. However, Perkinsus sp. was not found in four other species of clams nor R. philippinaurm collected from Kimnyong and Waido in Cheju. A size-dependent Perkinsus sp. infection was found in R. philippinarum collected rom Kangjin and Wando the clams smaller than 15mm in shell width do not exhibit and Perkinsus sp. while other clams greater than 20mm in shell width exhibit almost 100% infection. To determine the number of Perkinsus sp. in the clams, FTM cultured clam tissues were digested with 2M NaOH solution and the number of hypnospores in the tube were counted. The number of hypnospores counted from the tissues indicated that each Manila clam contains 100,000 to 3,500,000 Perkinsus cells or 20,000 to 1,000,000 cells per gram tissue wet weight. The results of cell counts also suggests that such a high occurrence of Perkinsus sp. in the clam may cause mortality, as already reported from other studies of Perkinsus spp.

• 농촌의학ㆍ지역보건
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• 제15권2호
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• pp.107-111
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• 1990

A survey was undertaken to evaluate the present status of intestinal infection in army soldiers. Stool specimen of 417 soldiers fixed by SAF solution were collected from a camp located in area of Nakdong river during the period from August to October of 1990. And these stool samples were examined by formalin-ether sedimentation technique once for helminths and protozoan cysts stained with Lugol's iodine solution. The results obtained in this survey were summarized as follows : l) The overall positive rate of intestinal parasite was 18.0%. 2) The egg positive rate of intestinal helminth was 15.1%, : and 11.5% for Clonorchis sinensis. 5.0% for Metagonimus vokogawai, 1.2% for Ascaris lumbricoides 1.7% for Trichiuris trichiura. 0.2% for Taenia sp. 3) The cyst positive rate of intestinal protozoa was 4.1% ; and 1.4% for Entamoeba coli, 1.9% for Giardia lamblia 0.7% for Entamoeba histolytica, 0.5% for Endolimax nana. 4) Most of samples were positive(85.3%) by single species. 10.7% by two species, 2.7% by three species and 1.3% by four species. 5) Infection rate of intestinal parasites among army soldiers decreased distinctly compared with previous data but it is revealed that the infection rate of Clonorchis sinensis among army soldiers in area of Nakdong river is still high in comparison with ever-reported data. 6) SAF fixatives used in this field survey during summertime was useful to conserve protozoan cyst and helminths ova. Also we could examine stool samples directly by formalin-ether sedimentation technique.

• Parasites, Hosts and Diseases
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• 제28권2호
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• pp.109-114
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• 1990

한국 가톨릭의사협회는 남미 에꽈돌국 과야스주의 해안 지방인 빨말 본당에서 운영하는 "빠띠마 성녀 기념 본당 진료소"의 의료사업을 지원하고 있다. 그 사업의 하나로 이 지역 메스띠조인의 보건 실태를 관찰하고 앞으로의 중점 보건 사업을 파악하기 의하여 1989년 8월 6일부터 8월 19일까지 주민 진료와 합께 대변검사를 실시하고 기생충 감염 실태를 조사하였다. 이 지역은 동부 태평양에 연한 해안 어촌 마을인 빨말(본당), 아양게, 함벨리(공소)와 해안에서 떨어져 있고 목축을 주업으로 하는 바빌 데세초, 리오세꼬, 밤빌꼬자오, 마난띠 알 데 꼴론체 및 세비자 등 공소마을로 구성되어 있고 주민은 모두 약 20,000명으로 추산된다. 대변검사는 직접 도말법(요드염색 후) 1매와 셀로판후층도말법 1매를 각각 검경하여 장내 원충 포낭 및 윤충 충란 배출을 검사하였다. 검사 대상자는 진료소를 찾은 주민이며 빨말 본당 지역의 주민 160명을 포함한 해안 마을 주민 226명과 내륙 공소 마을 주민 99명 등 모두 325명이었다. 대변검사 결과 충란 및 포낭 양성률이 66.1%이었고 윤충 충란 양성률은 38.2%, 원충 포낭 양성률은 56.1%이었다. 기생충별 양성률은 회충 18.1%, 편충 19.4%, 구충 0.6%, 왜소조충 3.7%, 유구 및 무구조충 1.8%, 이질아메바 19.4%, 대장아메바 28.6%, 소형아매바 5.5%, 요드아메바 1.5%, 람블편모충 11.1%, 킬로마스틱 스메니리 0.6%이었다. 이상의 결과를 종합하여 보면 이 지역에서 가장 중요한 기생충 감염은 이질 아메바와 람블편모충이며 따라서 위생적인 식수를 마련하는 것이 가장 중요한 보건사업이라고 판단되었다. 목축을 주로 하는 내륙 마을중에는 조충증과 유구낭미충증이 유행하는 지역이 있었다.