• KSBB Journal
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• v.15 no.3
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• pp.299-306
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• 2000

Concern for the effects of toxic chemicals on the environment leads the search for better bioassay test organisms and test procedures. Photobacterium phosphoreum was used successfully as a test organism and the luminometer detection technique was an effective and simple method for determining the concentration of toxic chemicals. With EC50 a total of 14 chlorine substituted phenols benzenes and ethanes were used for the experiments. The test results showed that the toxicity to P. phosphoreum increased in the order of phenol > benzene > ethane and the toxicity also increased with the number of chlorine substitution. Quantitative structure activity relationship (QSARO) model can be used to predict EC50 to save time and endeavor. Correlation was well established with the QSAR parameters such as log P, log S and solvatochromic parameter(Vi/100 $\pi$, ${\beta}$m and am). The QSAR modeling was used with multi-regression analysis and mono-regression analysis. These analyses resulted in the following QSAR : $log EC_{50} =2.48 + 0.914 log S(n=9 R2=85.5% RE=0.378) log EC_{50}=0.35 - 4.48 Vi/100 + 2.84 \pi^* +9.46{\beta}m-4.48am (n =14 R2=98.2% RE=0.012) log EC_{50} =2.64 -1.66 log P(n=5, R2=98.8% RE=0.16) log EC_{50}=3.44 -1.09 log P(n=9 R2= 80.8% Re=0.207)$

• Clinical and Experimental Reproductive Medicine
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• v.32 no.1
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• pp.47-54
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• 2005

Objective: Evaluation of embryos using early cleavage to 2-cell stage has been proposed, but a critical time-point for selecting embryos is unclear. The aim of the present study is to provide a guideline including critical time-point in the selection of early cleaving embryo for the reduction of multiple pregnancies as well as the increase of pregnancy rate in human IVF. Methods: This prospective study was performed in 116 cycles from 85 patients who underwent conventional IVF or ICSI at the infertility clinic of Good Moonhwa Hospital from January 2002 to December 2003. Early cleavage (EC) of embryos to 2-cell stage was assessed at 25 h and 27 h postinsemination/microinjection. Embryos that had early cleaved at each time point were designated as EC-1 and EC-2, respectively, while others were designated as non-early cleavage (NEC). Results: At least one early cleavage embryo was observed in 54 (46.6%) for the EC-1 and 84 (72.4%) for the EC-2 of the 116 cycles assessed. Clinical pregnancy rates (PR) were significantly higher in the EC-1 group (66.7%) compared to the EC-2 group (53.6%) or the NEC group (31.2%) (p<0.05). Significant improvement of the pregnancy rate was found when at least two or more embryos were early cleaved at 25 h postinsemination or when the proportion of early cleavage embryo at 25 h postinsemination was higher than 20% (p<0.05). Conclusion: The critical time-point for the selection of early cleavage embryos with high implantation potential is more effective in 25 h postinsemination/microinjection compared to 27 h. The proportion as well as number of early cleavage embryos is also an important factor for the prediction of pregnancy outcome and the chance of multiple pregnancies. These results demonstrated that the evaluation of early cleavage embryos to 2-cell stage is an easy, simple, and objective method for the selection of good quality embryos suitable for embryo transfer.

• Korean Journal of Environmental Agriculture
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• v.7 no.2
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• pp.102-110
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• 1988

This study was designed to find out whether the water quality of Lake Daeho would be suitable for Sgricultural purposes during 1984-1988 perird. Thr results were as follows ; 1. There was an apparent seasonal temperature fluctuation$(6-25^{\circ}C)$ above the entrance of the culvert at the depth of 14m, but the temperature below remained constant at $11,9^{\circ}C$. 2. The yearly water qualities observed at the deepest site by the seadike were 7.4-7.5 pH, 16,800-1,472 ${\mu}mhos/cm$ EC, 9.2-10.8ppm DO, 1.3-2.5ppm DOD, 2.4-5.3ppm COD, 0.22-2.29ppm T-N, 0.01-0.10ppm T-P. 3. The average values of water qualities at the epilimnion in 1988 were 7.6 pH, 1,745umhos/cm EC, 10.8ppm DO, 1.8ppm DOD, 2.4ppm COD, 0.52ppm T-N, 0.05ppm T-P. 4. The salinity of the epilimnion at a 6m depth was 29,000ppm before the final closure of the seadike. It was 11,000 ppm in March 1984, 4,300ppm in March 1985, 2,000ppm in March 1986 and 1987, and 900ppm in March 1988. The salinity of the whole water column decreased from 29.000ppm to 1,200 ppm in March 1988. The average salinity above and below the culvert in 1987 was about 1,300ppm, and 30,000ppm respectively reaching that of seawater. 5. The highest salinity was observed at the epilimnion by the seadike, showing about 5,835ppm in 1984. 6. The seasonal salinity fluctuation was 2,000ppm in May, 800ppm in October, and 485ppm in September 1987. 7. The halocline was observed at the depth of 14m where the entrance of the culvert was located. Therefore, the epilimnion water is suitable for agricultural purposes, and the intake of water from Lake Sapkyo seems to be unnecessary.

• Korean Journal of Plant Tissue Culture
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• v.26 no.1
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• pp.41-47
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• 1999

Phenylalanine ammonia-lyase (PAL; EC 4, 3, 1, 5) genomic clones were isolated from tomato(Lycopersicon esculentum L.) genomic DNA libraries using tomato PAL5 cDNA sequences as probes. The nucleotide sequences of tPAL1, tPAL4 and tPAL5 were compared. tPAL5 contains an open reading frame encoding a polypeptide of 722 amino acids, interrupted by a 710 bp intron in the codon for the amino acid 139. tPAL1 encodes a polypeptide of 249 amino acids which is much shorter than tPAL5 gene due to a premature stop codon and does not contain an intron. tPAL4 encodes a polypeptide of 357 amino acids, interrupted by a 305 bp intron in the codon for the amino acid 138. Premature stop codons observed in tPAL1 and tPAL4 gene produce a short polypeptide rather than a normal polypeptide (722 aa). tPALl shows 87.2% homology with tPAL4 and 85.3% homology with tPAL5 gene whereas tPAL4 showes 91.4% homology with tPAL5 at nucleotide level. In general, phylogenetic analysis showed that genes isolated from tomato, potato, and sweet potato were belong to the same group and another dicot plants such as parsley, bean, soybean, pea and alfalfa formed another group. PAL genes isolated from rice and yeast showed very low homology with other PAL genes and formed the other group.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.4
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• pp.333-339
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• 2016

The objective of this study was to optimize analytical methods for ochratoxin A (OTA) and zearalenone (ZEA) in rice straw silage and winter forage crops using ultra-high performance liquid chromatography (UHPLC). Samples free of mycotoxins were spiked with $50{\mu}g/kg$, $250{\mu}g/kg$, or $500{\mu}g/kg$ of OTA and $300{\mu}g/kg$, $1500{\mu}g/kg$, or $3000{\mu}g/kg$ of ZEA. OTA and ZEA were extracted by acetonitrile and cleaned-up using an immunoaffinity column. They were then subjected to analysis with UHPLC equipped with a fluorescence detector. The correlation coefficients of calibration curves showed high linearity ($R^2{\geq_-}0.9999$ for OTA and $R^2{\geq_-}0.9995$ for ZEA). The limit of detection and quantification were $0.1{\mu}g/kg$ and $0.3{\mu}g/kg$, respectively, for OTA and $5{\mu}g/kg$ and $16.7{\mu}g/kg$, respectively, for ZEA. The recovery and relative standard deviation (RSD) of OTA were as follows: rice straw = 84.23~95.33%, 2.59~4.77%; Italian ryegrass = 79.02~95%, 0.86~5.83%; barley = 74.93~97%, 0.85~9.19%; rye = 77.99~96.67%, 0.33~6.26%. The recovery and RSD of ZEA were: rice straw = 109.6~114.22%, 0.67~7.15%; Italian ryegrass = 98.01~109.44%, 1.65~4.81%; barley = 98~113.53%, 0.25~5.85%; rye = 90.44~108.56%, 2.5~4.66%. They both satisfied the standards of European Commission criteria (EC 401-2006) for quantitative analysis. These results showed that the optimized methods could be used for mycotoxin analysis of forages.