• Journal of Korean Society on Water Environment
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• v.34 no.4
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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.

• Journal of Korean Society on Water Environment
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• v.34 no.2
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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.

• Journal of Aquaculture
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• v.10 no.3
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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.

• Journal of agricultural medicine and community health
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• v.15 no.2
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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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• v.28 no.2
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• pp.109-114
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• 1990

Status of intestinal protozoan and helminthic infections was surveyed in mestizo population living in rural parish of Palmar and its nearby recintos(villages) , Three of the surveyed villages were at the Pacific coast and 5 villages were in inner pasture land, located about 100 km west of Guayaquil, the second largest city in Ecuador. One stool sample was examined by one cellophane thick smear for helminth ova and one direct smear stained with Lugol's iodine solution for protozoan cysts. Of 325 persons examined, 66.1% were positive for any ova or cyst. The positive rates were: 18.1% for Ascaris lumbricoides, 19.4% for Trichuris trichiura, 0.6% for hookworm, 3.7% for Hyntenolepis nana, 1.8% for Taenia sp., 19.4% for Entnmoeba histolytica, 28.6% for Entamoeba coli, 5.5% for Endolimax nasa, 1.5% for ledamoeba buetschlii, 11.l% for eiardia lamblia and 0.6% for Chilomastix mesnili. Poor supply of potable water was considered the main cause of high prevalence of intestinal protozoan infections.