• Ocean and Polar Research
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• v.31 no.4
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• pp.349-357
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• 2009

Ballast water is widely recognized as a serious environmental problem due to the risk of introducing non-indigenous aquatic species. In this study we aimed to investigate measures which can minimize the transfer of aquatic organisms from ballast water. Securing more reliable technologies to determine the viability of aquatic organisms is an important initiative in ballast water management systems. To evaluate the viability of marine phytoplankton, we designed the staining methods of fluorescein diacetate (FDA) and Calcein-AM assay on each target species belonging to different groups, such as bacillariphyceae, dinophyceae, raphidophyceae, chrysophyceae, haptophyceae and chlorophyceae. The FDA method, which is based on measurements of cell esterase activity using a fluorimetric stain, was the best dye for determining live cells of almost all phytoplankton species, except several diatoms tested in this study. On the other hand, although fluorescence of Calcein-AM was very clear for a comparatively longer time, green fluorescence per cell volume was lacking in most of the tested species. According to the Flow CAM method, which is a continuous imaging technique designed to characterize particles, green fluorescence values of stained cells by FDA were significantly higher than those of Calcein-AM treatments and control, implying that the Flow CAM using FDA assay could be adapted as an important tool for distinguishing living cells from dead cells. Our results suggest that the FDA and Calcein-AM methods can be adapted for use on phytoplankton, though species-specific characters are greatly different from one organism to another.

• Korean Journal of Microbiology
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• v.24 no.2
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• pp.147-153
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• 1986

Viable potential of Mycobacterium smegmatis, a slow grower in vitro cultivation and of M. leprae, an obligate intracellular parasitic bacterium, which can not be cultured yet in vitro was assessed by fluorospectrophotometry. Bacterial cells in different numbers and under various physiological status were incubater with fluorescein diacetate(FDA). After an incubation of the bacterial preparations with FDA at specified conditions, amount of fluorescein inside bacteria was measured by a fluorospectrophotometer at 470nm and 510nm of excitation and emission wavelengths, respectively. Fluorounit given by such bacteria showed a correlation with assessment of viability of the same preparations made by other methods, such as optical density and colony forming units of M. smegmatis and intracellular ATP content of M. leprae. The possible use of fluorospectrophotometry in assessing viability or physiological potential of bacteria, particularly intracellular parasites and fastidious organisms to culture in vitro is discussed in relation to other methods.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.354-361
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• 2014

This study was conducted to investigate whether several composted liquid manures (CLMs) are useful for biological control of large patch on zoysiagrass and investigate the chemical and biological factors to suppress large patch in soil treated with CLMs. The CLMs were produced at 4 different facilities for livestock excretion treatments located in Korea. Field experiments were carried out at 5 golf courses located near each facility. CLM and Chemical fertilizer (CF: water soluble fertilizer, 20-20-20) were applied four and three times with N at $12g\;m^{-2}$ per year, respectively. There was significant increase of concentration of K, Na, and Cu of soil treated with CLM compared to CF treatment. Among experimental plots, CN and GG2 plot sites were shown significant higher effect of biological control 80% and 50% respectively against large patch disease. The number of bacteria, Actinomycetes, and fungi in soil at these sites significantly increased and fluorescein diacetate hydrolytic activity was enhanced, while the soil was treated with CLM. The results of this study demonstrated that CLM application has effect on soil to suppress large patch and reduce the use of fungicide in environment-friendly turf management.

• Horticultural Science & Technology
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• v.17 no.3
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• pp.337-340
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• 1999

In order to evaluate stored apple pollen viability, in vitro germination test was performed on a microscope slide coated with the culture medium containing fluorescein diacetate (FDA). However, the inclusion of FDA to the culture medium declined pollen germination. Alternatively, the fluorochromatic reaction procedure was tested. The procedure involved dusting pollen grains onto drops of 10% sucrose solution containing 0.002% FDA and allowing them to accumulate fluorescein. Within 30 min after the fluorochromatic reaction, viable pollen grains clearly fluoresced under ultraviolet light. Both the in vitro germination test and the fluorochromatic reaction procedure revealed that stored apple pollen viability was not considerably decreased over storage up to at least 39 months. Of the cultivars examined by both methods, 'Fuji' and 'Senshu' pollen viability was highest, 'Tsugaru' was intermediate, and 'Jonagold' was lowest. The fluorescing percentages appeared approximately comparable to the germination percentages except for the 'Senshu' pollens stored for 3 months, although the fluorescing percentages was slightly higher than the germination percentages. Strong and highly significant correlations were found between the two methods. It can thus be concluded that the fluorochromatic reaction procedure provides a convenient and reliable evaluation of stored apple pollen viability.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.4
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• pp.223-231
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• 2014

In order to prevent the spread of non-indigenous aquatic species through the ballast water in commercial ships, International Maritime Organization (IMO) adopted in 2004 the International Convention for Control and Management of Ship's Ballast Water and Sediments. The Convention mandates treatment of ballast water for most transoceanic voyages and its confirmation of treatment is made with plankton live/dead assay. Fluorescein diacetate assay (FDA), which produces bright green light for live phytoplankton, has been a de facto standard method to determine the survival of marine plankton, but its staining efficacy has been in dispute. In the present study, we examined the limitation of FDA, and compared its efficacy with Neutral red (NR) staining, another promising assay and widely used especially for zooplankton mortality. For all phytoplankton species studied in the present study, except Ditylum brightwellii, the staining efficiency was <50% with FDA. The green FDA fluorescence interfered with phytoplankton autofluorescence in most samples. In contrast, NR assay stained over 90% of both phytoplankton and zooplankton species tested in this study. FDA assay also showed that green FDA fluorescence rapidly faded when phytoplankton cells were exposed to microscope light. Both FDA and NR assay were negative on formalin-killed individuals of both phytoplankton and zooplankton species. Our results suggest that NR assay is more effective for determining the survival of marine plankton and can be applied to test the efficacy of ballast water treatment.

• Korean Journal of Microbiology
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• v.32 no.2
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• pp.163-171
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• 1994

The effects of diesel oil on the microbial community in sandy loam soil were investigated, and the effects of bioremediation which was performed to enhance the removal of diesel oil from soil were also measured. The residual percentage of diesel oil was about 50% after 16 week incubation period. The bioremediation treatment increased the removal rate at 60~95%. When the soil was contaminated with diesel oil, the direct bacterial count, length of fungal hyphae, aerobic heterotroph and hydrocarbon degrader were increased by 2~3 orders of magnitude. The bioremediation further increased these numbers 10 to 100-fold. There were no difinite patterns of change in fluorescein diacetate hydrolysis activity in bioremediation-untreated soil, but about 10 times of increase of activity was observed in bioremediation-treated soil. Similar change was occurred in soil dehydrogenase activity.

• Clinical and Experimental Reproductive Medicine
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• v.19 no.1
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• pp.1-8
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• 1992

A fluorescence microscopy technique using flurescein diacetateCFDA) as a substract has been tested for the evaluation of the viability of early mouse embryos. Embryos were incubated in T6 containing FDA concentrations of 2.5 to $50{\mu}g/ml$ for 1 to 5min. Embryos were then examined by reflected light fluorescence using a KP 490 and 520 barrier filter in a Nicon Diaphot microscopy. The results were as follow. 1. The rate of fluorescein accumulation increased on the concentration on FDA from $2.5{\times}10^{-6}M$ to $20{\times}10^{-6}M$ 2. The rate at which intracellular fluorescein was lost from embryos was depended on the temperature at which are stored. 3. Embryos with 3 min exposure to FDA have the most intensity of fluorescence. 4. Exposure of 2 cell embryos to FDA ($2.5-5{\mu}g/ml$) for 1 min did not alter their ability to delope normally in vitro.

• Natural Product Sciences
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• v.7 no.3
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• pp.72-75
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• 2001

The antioxidant activity of roasted defatted perilla (Perilla frutescens) seed was determined by measuring its radical scavenging effect on 1,1-diphenyl-2- picrylhydrazyl (DPPH) radicals, inhibitory activity on total reactive oxygen species generation in kidney homogenates using 2',7'-dichlorodihydro-fluorescein diacetate, and scavenging effect on authentic peroxynitrites. The methanolic extract of roasted defatted perilla seed showed strong scavenging activity in both DPPH and peroxynitrite radicals, and thus fractionated with several solvents. The antioxidant activity potential of the individual fraction was in the order of ethyl acetate>n-butanol>dichloromethane>water>n-hexane fraction. The ethyl acetate soluble fraction exhibiting strong antioxidant activity was further purified by repeated silica gel and Sephadex LH-20 column chromatography. Luteolin was isolated as one of the active principles from the ethyl acetate fraction, together with the inactive chrysoeriol and apigenin.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.196-201
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• 2000

The influence of adsorption on cadmium toxicity to soil microorganisms in smectite-rich soils and sediments was quantified as a function of solution and sorbent characteristics. Adsorption and surface complexation experiments were conducted to infer Cd sorption mechanisms to a reference smectite and three fractions of a Veritsol soil, and to elucidate the effects of the surface complexation on Cd bioavailability and toxicity in soils and sediments. Cadmium adsorption isotherms conformed to the Langmuir adsorption model, with adsorptive capacities of the different samples dependent on their characteristics. Equilibrium geochemical modeling (MINTEQA2) was used to predict the speciation of Cd in the soil suspensions using Langmuir and Triple Layer surface complexation models. The influence of adsorption and surface complexation on cadmium toxicity to soil microorganisms was assessed indirectly through the relative change in microbial hydrolysis of fluorescein diacetate (FDA) as a function of total Cd concentration and sorbent characteristics. Adsorption decreased the toxicity of Cd to soil microorganisms. Inner-sphere complexation is more effective than outer-sphere complexation in reducing the bioavailability and toxicity of heavy metals in soils and sediments.

• Environmental Engineering Research
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• v.22 no.2
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• pp.224-229
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• 2017

Zinc oxide nanoparticles (ZnO NPs) have been used as additives in a variety of consumer products. While these particles may enter the environment, only a limited number of studies have investigated the effects of ZnO NPs on soil exoenzymes. Here, we investigate the long-term effects of ZnO NPs at concentrations of 50 and 500 mg/kg on the activities of six soil exoenzymes in planted soils: Dehydrogenase, fluorescein diacetate (FDA) hydrolase, urease, acid phosphatase, arylsulfatase, and ${\beta}-glucosidase$. Significant effects were observed at one or more time points for all enzymes except for FDA hydrolase. These effects included both decreases and increases in enzyme activity. Our results suggest that ZnO NP treatments of 50 and 500 mg/kg can adversely affect soil enzymes, particularly acid phosphatase and urease, and thus, these data may have implications for phosphorous and nitrogen cycles in the soil.