• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.5
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• pp.323-326
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• 2002

To detect whole ammonia-oxidizing bacteria in the activated sludge, group-specific primers targeting the 16S-rRNA gene of ammonia-oxidizing bacteria were used. The electrophoresis pattern of the PCR products seemed to produce a single band of approximately 1.0 k bp for the bacteria in activated sludge and Nitrosomonas europaea. No band was observed for nitrite-oxidizer Nitrobacter winogradskyi and heterotrophs such as Pseudomonas putida. Then direct measurement of the PCR product was made by fluorometry using the reagent Hoechist 33258, so that the fluorescent intensity was in proportional to the cell number of the sample up to 240. Total time required for the test was about 4 h including DNA extraction. The DNA fragments produced were cloned and their sequences showed high similarity to those of Nitrosomonas spp. This study showed the feasibility to detect ammonia-oxidizing bacteria and to esti-mate their population rapidly for the control of the nitrogen elimination process.

• Korean Journal of Veterinary Research
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• v.13 no.1
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• pp.23-30
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• 1973

Thin layer, paper and column chromatography were compared for the separation, detection and quantitation of three kinds of estrogen in urine of dairy cows. While thin layer chromatography utilizing silica gel was better for the detection of estrogens, column chromatography using celite 545 was preferable. Spectrophotometry was compared with fluorometry for determination of estrone, estradiol-17 ${\beta}$ and estriol eluted by paper chromatography and column chromatography. Optical density of three standard estrogens showed almost same curve at maximum absorption wave length of 230 and $282m{\mu}$. However, the former showed a higher peak. In fluorometry, the fluorescence intensity of estrone and estradiol-17 ${\beta}$ were rather strong, when the estrogens were dissolved in sulfuric acid, and showed higher sensitivity than that of the spectrophotometry. However, in the case of estriol was exceptional.

• Korean Journal of Environmental Biology
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• v.26 no.2
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• pp.76-86
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• 2008

The seasonal variations of primary production were investigated by phyto-PAM chlorophyll fluorometry as well as classical methods (standing crops of phytoplanktons and chlorophyll ${\alpha}$) in the Beopsu Marsh, Haman-gun, Gyeongsangnam-do. The amounts of turbidity, SS, T-N, T-P, BOD, COD, Ca$^{2+}$ and Cl$^-$ were the highest at the station 3, where located in flowout site of wastewater treated by the filtration plants. The water quality was the third level by the standard of BOD and COD. The amount of chlorophyll a (268.8 mg L$^{-1}$) was the highest at the station 2 in April because the cell density (2,677 cells mL$^{-1}$) of Micractinium pusillum increased suddenly from February (180 cells mL$^{-1}$). The patterns of primary production of phytoplankton by phyto-PAM chlorophyll fluorometry were fallen in with those of standing crops and chlorophyll a of phyto-planktons. The primary production was varied according to stations and seasons. The water environments of the Beopsu Marsh as a natural mounument should be under the control of a regular examination in order to preserve the ecosystem.

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.26-27
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• 2005

• Journal of Photoscience
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• v.7 no.4
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• pp.155-159
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• 2000

[Ru(bpy)$_2$(dppz)]$^2$$^{+}$ (bpy = 2,2'-bipyridine, dppz = dipyrido[3,2-a:2',3'-c]phenazine)(RuBD), a long-lifetime metal-ligand complex displays photophysical properties including long lifetime, polarized emission, and very little background fluorescence. To further show the usefulness of this luminophore(RuBD) for probing nucleic acid dynamics, its intensity and anisotropy decays when bound to tRN $A^{val}$ were examined using frequency-domain fluorometry with a blue light-emitting diode(LED)as the modulated light source. Unexpectedly much longer mean lifetime was obtained at 4$^{\circ}C$(<$\tau$>=178.3 ns) as compared to at $25^{\circ}C$(<$\tau$>=117.0 ns), suggesting more favorable conformation of tRN $A^{val}$ for RuBD when intercalated at 4$^{\circ}C$. The anisotropy decay data showed longer rotational correlation times at 4$^{\circ}C$(52.7 and 13.0 ns) than at $25^{\circ}C$ (32.9 and 10.3 ns). The presence of two rotational correlation times suggests that RuBD reveals both local and overall rotational motion of tRN $A^{val}$. Due to long lifetime of RuBD and small size of tRN $A^{val}$, very low steady-state anisotropy values were observed, 0.048 and 0.036 at 4 and $25^{\circ}C$, respectively. However, a clear difference in the modulated anisotropy values was seen between 4 and $25^{\circ}C$. These results indicate that RuBD can be useful for studying hydrodynamics of small nucleic acids such as tRN $A^{val}$.^{val}$.>.$.>.

• BMB Reports
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• v.34 no.6
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• pp.551-558
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• 2001

We extended the measurable time scale of DNA dynamics to submicrosecond using a long-lifetime metal-ligand complex, $[Ru(phen)_2(dppz)]^{2+}$ (phen=1,10-phenanthroline, dppz=dipyrido[3,2-a:2',3'-c]phenazine) (RuPD), which displays a mean lifetime near 350 ns. We partially characterized the fluorescence resonance energy transfer (FRET) in calf thymus DNA from RuPD to nile blue (NB) using frequency-domain fluorometry with a high-intensity, blue light-emitting diode (LED) as the modulated light source. There was a significant overlap of the emission spectrum of the donor RuPD with the absorption spectrum of the acceptor NB. The F$\ddot{o}$rster distance ($R_0$) that was calculated from the spectral overlap was $33.4\;{\AA}$. We observed dramatic decreases in the steady-state fluorescence intensities of RuPD when the NB concentration was increased. The intensity decays of RuPD were matched the closest by a triple exponential decay. The mean decay time of RuPD in the absence of the acceptor NB was 350.7 ns. In a concentration-dependent manner, RuPD showed rapid intensity decay times upon adding NB. The mean decay time decreased to 184.6 ns at $100\;{\mu}M$ NB. The FRET efficiency values that are calculated from the mean decay times increased from 0.107 at $20\;{\mu}M$ NB to 0.474 at $100\;{\mu}M$ NB concentration. The use of FRET with a long-lifetime metal-ligand complex donor is expected to offer the opportunity to increase the information about the structure and dynamics of nucleic acids.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.1
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• pp.76-87
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• 2014

Chlorophyll a in seawater which is an indicator of phytoplankton biomass and primary production is determined by High Performance Liquid Chromatography (HPLC), Fluorometry and Spectrophotometry. In this study, various methods for chlorophyll a determination in seawater are compared using in situ seawater samples from Korean seas. Three inter-laboratory comparison campaigns were carried out using chlorophyll a standard samples (R0) and in situ seawater samples, collected from the East China Sea (R1) and the East Sea (R2). 6 laboratories by HPLC methods, 4 laboratories by fluorometry, and 3 laboratories by spectrophotometry participated. Precisions, defined as the coefficient of variation (CV) were within 9% in standard samples, 0.8~20% (average: 6.1%) in R1, 4~21% (average: 13.2%) in R2. Discrepancy in three methods was approximately 20% within the range of the sample homogeneity intended the laboratory precision (R1: 8%, R2: 15%). The discrepancy in laboratories was greater than the discrepancy in methods. The chlorophyll a concentrations can be produced within 20% discrepancy in spite of using different methods. It is recommended to consider this 20% discrepancy when using the chlorophyll a data produced by different laboratories and different methods.

• Journal of Photoscience
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• v.11 no.1
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• pp.35-40
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• 2004

[Ru(2,2'-bipyridine)$_2$(4,4'-dicarboxy-2,2'-bipyridine)]$^{2+}$(RuBDc) is a very photostable probe that possesses favorable photophysical properties including long lifetime, high quantum yield, large Stokes' shift, and highly polarized emission. To evaluate the usefulness of this luminophore (RuBDc) for studying macromolecular dynamics, its intensity and anisotropy decays when conjugated to RNA bacteriophage MS2 were examined using frequency-domain fluorometry with a high-intensity, blue light-emitting diode (LED) as the modulated light source. The intensity decays were best fit by a sum of two exponentials, and the mean intensity decay time was 442.2 ns. The anisotropy decay data showed a single rotational correlation time (2334.9 ns), which is typical for a spherical molecule. The use of RuBDc enabled us to measure the rotational correlation time up to several microseconds. These results indicate that RuBDc can be useful for studying rotational diffusion of biological macromolecules.s.

• Archives of Pharmacal Research
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• v.4 no.1
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• pp.19-24
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• 1981

The possibility of using a fluorescence probe technique for the study of ibuprofenlysine binding to human and bovine serum albumin was investigated. 1-anilino-8-naphalenesulfonate was used as the probe. The number of binding sites of human and bovine serum albumins for ibuprofenlysine appears to be 4 and 2, respectively. By using this technique, the association constants were found to be $1.533{\times}10^{4}M^{-1}$ and $2.238{\times}10^{4}M^{-1}$, respectively.

• Archives of Pharmacal Research
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• v.7 no.2
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• pp.109-113
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• 1984

The critical micelle concentration (CMC) of crude ginseng saponin in water was determined by fluorometry and surface-tension measurement. These two methods gave the the CMC value, 0.015g/100ml AND 0.013G/100ml, respectively. The surface excess of the saponin and the area occupied by a saponin molecule at the monolayer adsorbed at air and waterinterface were calculated employing Gibbs adsorption equation. The presence of salt increased the surface activity of the saponin: it decreased the CMC, the surface tension at the CMC and the area occupied by a saponin molecule at the monolayer, which should be due to the salting-out effect of the salt.