• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.904-908
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• 2007

The protozoan pathogen Giardia lamblia has been major cause of waterborne enteric disease. In this study, we tried to identify G. lamlbia of human infectious species and to detect viable C. lamblia in river water samples including three sites of Han River mainstream and an its creek using PCR and RT-PCR technique. The PCR/RT-PCR methods were performed by using giardin primer based on the giardin gene targeting ventral disk of Giardia. Sensitivity testing in the DNA/RNA extraction and PCR/RT-PCR amplification steps showed that it was possible to detect a single cyst of G. lamblia and viable G. lamblia. The PCR/RT-PCR methods were compared with immunofluorescence(IF) assay by analyzing 48 samples collected from the mainstream water and the creek water. The mean concentration of the total cysts were 6.3 cysts/10 L(arithmetic mean, n = 48) and the positive detection rate were 62.5%(30/48). And the mean concentration of the cysts excluding empty cysts were 4.5 cysts/10 L and the positive detection rate were 52.1%(25/48). It resulted that 24 of 48 samples included Giardia lamblia by PCR assay and 10 of 48 samples included viable G. lamblia by RT-PCR assay. It resulted that the PCR/RT-PCR technique would be available to river water samples with low concentration of Giardia cysts. And it could support the Korean protozoan standard method, which provides useful information for species and viability.

• Microbiology and Biotechnology Letters
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• v.35 no.1
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• pp.11-16
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• 2007

The arylsulfatase gene (astA, 984 bp ORF) from Pseudoalteromonas carrageenovora genome was amplified by PCR and subcloned into the pHCE-IA vector, in which the hyper consitutive expression (HCE) promoter from the D-amino acid aminotransferase (D-AAT) gene of Geobacillus toevii was employed. The transformant cell, Escherichia coli BL21 (DE3)/pHCE-AST, on LB agar plate containig 4-methylumbelliferyl sulfate, showed an intense fluorescence at 360 nm, indicating that 4-methylumbelliferone was liberated by desulfatate activity. When BL21 (DE3)/pHCE-AST was grown on LB media containing 0.4% glucose or 0.4% glycerol, the arylsulfatase activity was higher at glycerol rather than at glucose. On 2% glycerol medium, the arylsulfatase activity reached 15.0 unit/ml, which was 2.6-fold higher expression level than that with 1% glycerol. The DNA ladder in agarose prepared from agar by this recombinant enzyme revealed similar resolution and migration patterns with a commercial agarose. This results suggests that arylsulfatase overexpressed in E. coli could be applicable to the economic production of electrophoretic-grade agarose.

• Progress in Medical Physics
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• v.10 no.1
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• pp.41-46
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• 1999

There is necessity for making a smaller and more sensitive detector in small field sizes. This report assesses the suitability of metal-loaded thermoluminescent dosimeters for this purpose. Measurements were performed in the 6 MV photon and 6 MeV electron beams of a medical linear accelerator with LiF thermoluminescence dosimeters (TLD-100) embedded in solid water phantom. TLD-100 chips(surface area 3.2 $\times$ 3.2 $\textrm{mm}^2$) loaded with a metal plate(Tin or gold respectively) were used to enhance dose readings to TLD-100. Surface dose was measured for field size 10 $\times$ 10 $\textrm{cm}^2$ and 100 em SSD. Measurements have been made of the enhanced signal intensity and good linearity for absorbed dose with each metal. Using a 1 mm each metal on TLD-l00 in the beam increased the surface dose to 14% and 56% respectively for 6MV photon. In the case of 6 MeV electron, gold plate enhanced the TL response to 13%, but there is no difference for tin plate. The specific dose response of TLD-100 with thin metal plate increases with electron concentration of metal film, this is most likely due to increased electron scattered from the additional material with electron density higher than TLD-100. This emphasizes the role of TL dosimeters with metal as amplified dosimeters for therapeutic high energy x-ray beams. Due to the enhanced dose reading of TLD-100 with metal plate, it could be possible to develop smaller TL dosimeter with high sensitivity.