• Journal of Plant Biotechnology
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• v.2 no.2
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• pp.61-71
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• 2000

By screening a cDNA library of auxin-treated mung bean (Vigna radiata L.) hypocotyls, we have isolated two full-length cDNA clones, pVR-ACS6 and pVR-ACS7, for 1-aminocyclopropane-1-carboxylate (ACC) synthase, the rate-limiting enzyme in the ethylene biosynthetic pathway. While PVR-ACS6 corresponds to the previously identified PCR fragment pMBA1, pVR-ACS7 is a new cDNA clone. A comparison of deduced amino acid sequences among auxin-induced ACC synthases reveal that these enzymes share a high degree of homology (65-75%) to VR-ACS6 and VR-ACS7 polypeptides, but only about 50% to VR-ACS1 polypeptide. ACS6 and ACS7 are specifically induced by auxin, while ACS1 is induced by cycloheximide, and to lesser extent by excision and auxin treatment. Results from nuclear run-on transcription assay and RNA gel blot studies revealed that all three genes were transcriptionally active displaying unique patterns of induction by IAA and various hormones in etiolated hypocotyls. Particularly, 24-epibrassinolide (BR), an active brassinosteroid, specifically enhanced the expression of VR-ACS7 by distinct temporal induction mechanism compared to that of IAA. In addition, BR synergistically increased the IAA-induced VR-ACS6 and VR-ACS7 transcript levels, while it effectively abolished both the IAA- and kinetin-induced accumulation of VR-ACS1 mRNA. In light-grown plants, VR-ACS1 was induced by IAA in roots, whereas W-ACS6 in epicotyls. IAA- and BR-treatments were not able to increase the VR-ACS7 transcript in the light-grown tissues. These results indicate that the expression of ACC synthase multigene family is regulated by complex hormonal and developmental networks in a gene- and tissue-specific manner in mung bean plants. The VR-ACS7 gene was isolated, and chimeric fusion between the 2.4 kb 5'-upstream region and the $\beta$-glucuronidase (GUS) reporter gene was constructed and introduced into Nicotiana tobacum. Analysis of transgenic tobacco plants revealed the VR-ACS7 promoter-driven GUS activity at a highly localized region of the hypocotyl-root junction of control seedlings, while a marked induction of GUS activity was detected only in the hypocotyl region of the IAA-treated transgenic seedlings where rapid cell elongation occurs. Although there was a modest synergistic effect of BR on the IAA-induced GUS activity, BR alone failed to increase the GUS activity, suggesting that induction of VR-ACS7 occurs via separate signaling pathways in response to IAA and BR.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1520-1520
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• 2001

Food adulteration is a serious consumer fraud and a potentially dangerous practice. Regulatory authorities and food processors require a rapid, non-destructive test to accurately confirm authenticity in a range of food products and raw materials. Olive oil is prime target for adulteration either on the basis of the processing treatments used for its extraction (extra virgin vs virgin vs ordinary oil) or its geographical origin (e.g. Greek vs Italian vs Spanish). As part of an investigation into this problem, some preliminary work focused on the ability of near infrared spectroscopy to discriminate between virgin olive oils from separate regions of the Mediterranean i. e. Crete and the Peloponese. A total of 46 oils were collected: 18 originated in Crete and 28 in the Peloponese. Oils were stored in a temperature-controlled room at 2$0^{\circ}C$ prior to spectral collection at room temperature (15-18$^{\circ}C$). Samples (approximately 0.5$m\ell$) were placed in the centre of the quartz window in a camlock reflectance cell; the gold-plated baking plate was then gently placed into the cell against the glass so as to minimize the formation of air bubbles. The rear of the camlock cell was then screwed into place producing a sample thickness of 0.5mm. Spectra were recorded between 400 and 2498nm at 2nm intervals on a NIR Systems 6500 scanning monochromator. Spectral collection took place over 2-3 days. Data were analysed using both WINISI and The Unscrambler software to investigate the possibility of discriminating between the oils from Crete and the Peloponese. A number of data pre-treatments were used and discriminant models were developed using discriminant PLS (WINISI & Unscrambler) and SIMCA (Unscrambler). Despite the small number of samples involved, a satisfactory discrimination between these two oil types was achieved. Graphical examination of principal component scores for each oil type also holds out the possibility of separating oils from either Crete and the Peloponese on the basis of districts within each region. These preliminary data suggest the potential of near infrared spectroscopy to act as a screening technique for the confirmation of geographic origin of extra virgin olive oils. The sample presentation strategy adopted uses only small volumes of material and produces high quality spectra.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.382-388
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• 2018

In this study, the SELEX method was used to screen for and select aptamers with high selectivity and affinity for Streptococcus mutans, which is the causative agent of dental caries. Aptamers are single stranded oligonucleotides of DNA or RNA with high selectivity and affinity for target molecules because of their specific three-dimensional structures that are used to collect biometric information. When compared to antibodies in vitro, aptamers are more advantageous because of their ease of use in the screening process, low cost, chemical stability, and lack of restrictions on the target molecules. We sorted DNA aptamers, which contain 44 bp or 38 bp primer sequences in 5' and 3', 39 bp random sequences in the middle.We then analyzed the character and affinity to S. mutans. Aptamers of specific oligonucleotides that combine with S. mutans were selected and these results are selectively fused to S. mutans. The results confirmed that DNA aptamers can be used for rapid diagnosis and treatment of dental caries caused by bacteria of the oral cavity, namely S. mutans.

• Biomedical Science Letters
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• v.2 no.1
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• pp.41-48
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• 1996

The C-reactive protein(CRP) from ascitic and pleural fluid was purified using calcium dependent affinity chromatography of CNBr activated Sepharose-4B covalently coupled to p-diazonium phenylphosphorylcholine(DPPC) and hydroxylapitite chromatography. Polyclonal antibody was prepared from rabbit by immunizing the purified CRP. Specific immunoglobulin G was isolated using affinity chromatography and coupled to microparticles. A sensitive microparticle-based immunoassay was developed to measure CRP within 3 mins. The detection range was between 0.5mg/dl) and 20mg/dl in serum, showing strong response in the range of 0.7~2.9 mg/dl, weak response in 5.0~13.2 mg/dl and zone phenomenon over 28mg/dl. The average value of CRP in 74 samples was 3.8mg/dl and most of the values were lower than 10mg/dl .The CRP values of serum samples were determined by our microparticle-based immunoassay, and were compared with those obtained using the other commercial products(B Co., France and I Co., Japan). Good correlations were shown between the values obtained by our developed microparticle-based immunoassay system and those by other commercial products. All performance characteristics evaluated make our developed microparticles-based immunoassay suitable for a simple, rapid, and reliable screening of CRP in serum.

• Journal of Food Hygiene and Safety
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• v.32 no.3
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• pp.199-205
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• 2017

Although many PCR-based assays have been developed, the majority of rapid detection of Toxoplasma gondii in animal and their meat product has been dependent on immunogenic assays. Thus, there is still a need for more reliable PCR based detection method for T. gondii in retail meats. Recently, a 529-bp repeat element that exists in 200-300 copies per genome of T. gondii genome had been spotlighted for its usefulness as potential detection targers. In this study, the 529-bp repeat element was selected for real-time PCR to detect three types of T. gondii (type I, II and III). A primer pair targeting 82-bp of the 529-bp element detected all three types of T. gondii and showed high level of specificity against 14 different food-borne pathogens as well as 3 protozoan parasites such as Giardia lamblia, Cryptosporidium parvum and Entamoeba histolytica. Application of the new real-time PCR assay in meat samples showed improved detection sensitivity compared to the B1-gene targeted method suggesting potential new target for Toxoplasma gondii screening in retail meats.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1152-1161
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• 2007

An immunochromatography (ICG) strip test based on a monoclonal antibody for the rapid detection of L. monocytogenes in meat and processed-meat samples was developed in this study. A monoclonal antibody (MAb) specific to L. monocytogenes was produced from cloned hybridoma cells (FKLM-3B12-37) and used to develop an ICG strip test. The antibody showed a stronger binding to L. monocytogenes than other Listeria species, and a weak cross-reaction to S. aureus based on an ELISA. The detection limit of the ICG strip test was $10^5\;cell/ml$. In total, 116 meat and processed-meat samples were collected and analyzed using both the ICG strip test and a PCR. The ICG strip test and PCR indicated L. monocytogenes contamination in 34 and 27 meat samples, respectively. The 7 meat samples not identified as L. monocytogenes positive by the PCR were also tested using an API kit and found to be contaminated by Listeria species. In conclusion, the ICG strip test results agreed well with those obtained using the PCR and API kit. Thus, the developed ICG has potential use as a primary screening tool for L. monocytogenes in various foods and agricultural products, generating results within 20 min without complicated steps.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.906-911
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• 1999

This study was to determine whether DNA 'Comet Assay' can be applied to the detection of grains irradiated with low doses of Co-60 gamma radiation. Sesame, perilla, wheat, barley and rice were exposed to different doses of 0.1, 0.3, 0.5, 0.7 and 1.0 kGy. The cells isolated from the samples were embedded in a agarose gel on a microscope slide, lysed in lysis solution, and subjected to electrophoresis. DNA and its fragments migrated in the gel produced the characteristic pattern of DNA comet, of which the tail length was measured in a microscope. All the samples irradiated at 0.3 kGy and higher were applicable to detect post-irradiation by the tail length of their comets. Irradiated samples showed comets with long tails and their tail length increased with the dose, while unirradiated samples showed no or very short tails. Especially, sesame, perilla and wheat irradiated at 0.1 kGy could be distinguished from unirradiated samples by visual inspection of the slide in a microscope. Thus, DNA 'Comet Assay' might be applied to the detection of irradiated grains as a simple, inexpensive and rapid screening test.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.791-795
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• 2013

The aim of this study was to compare the performance of a standard culture method and polymerase chain reaction (PCR) for the detection of Staphylococcus aureus (S. aureus) in milk and meat products. Milk, dried infant formula, sausage and ground beef that had been artificially inoculated with S. aureus were enriched in tryptic soy broth. After the enrichment, a loopful was inoculated onto Baird-Parker agar with egg-yolk-tellurite. In parallel, 23S rRNA was amplified by PCR from samples of the enriched broth. Suspected S. aureus colonies grown on selective agars were finally confirmed by a coagulase test and colony PCR. No significant statistical differences were observed between the incidence of S. aureus detected by the culture method and the incidence detected by PCR, in milk or dried infant formula. However, in sausage and ground beef, the number of positives detected by PCR was significantly higher than by the culture method (p<0.05). Our findings suggest that PCR could be an effective screening tool for the detection of S. aureus compared to the standard culture method.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.9005-9008
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• 2014

Background: Gastric cancer is the second leading course of cancer death worldwide and H. pylori infection is an important risk factor for gastric cancer development. This study was design to evaluate the clinical, pathological features, survival rate and prevalence of H. pylori infection in gastric cancer in Thailand. Materials and Methods: Clinical information, histological features, endoscopic findings and H. pylori status were collected from gastric cancer patients from Thammasat university hospital during June 1996-December 2011. H. pylori infection was assessed by histological evaluation, rapid urease test and serological test. Clinical information, endoscopic findings and histopathology of all patients were recorded and compared between patients with active or non-active H. pylori infection. Results: A total of 100 gastric cancer patients (55 men and 45 women with mean age of $55{\pm}16.8years$) were enrolled in this study. Common presenting symptoms were dyspepsia (74%), weight loss (66%), anemia (63%) and anorexia (38%). Mean duration of symptoms prior to diagnosis was 98 days. Overall prevalence of H. pylori infection was 83% and active H. pylori infection was 40%. 1-year and 5-year survival rates were 43% and 0%. There was no significant difference between active H. pylori infection in different locations (proximal vs non-proximal: 47.1% vs 48.5%; P-value = 0.9, OR=0.9; 95%CI=0.3-3.1) and histology of gastric cancer (diffuse type vs intestinal type: 47.4% vs 50%; P-value = 0.8, OR=0.9, 95%CI=0.3-2.7). However, linitis plastica was significantly more common in non-active than active H. pylori infection (27.9% vs 0%; P-value<0.0001, OR=13.3, 95%CI=3.2-64.5). Moreover, gastric cancer stage 4 was higher in non-active than active H. pylori infection (93% vs 50%, P-value<0.001). Conclusions: Prevalence of H. pylori infection in Thai gastric cancer patients was high but active infection was low. Most gastric cancer patients presented in advance stage and had a grave prognosis. Screening for gastric cancer in high risk individuals might be an appropriate tool for early detection and improve the treatment outcome for this particular disease in Thailand.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.1971-1982
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• 2017

Piliated Lactobacillus rhamnosus (pLR) strains possess higher adherent capacity than non-piliated strains. The objective of this study was to isolate and characterize probiotic pLR strains in human fecal samples. To this end, mouse polyclonal antiserum (anti-SpaA) against the recombinant pilus protein (SpaA) of L. rhamnosus strain GG (LGG) was prepared and tested for its reactivity and specificity. With the anti-SpaA, a method combining the de Man, Rogosa, and Sharpe (MRS) agar plating separation and colony immunoblotting (CIB) was developed to isolate pLR from 124 human fecal samples. The genetic and phenotypic characteristics of the resultant pLR isolates were compared by randomly amplified polymorphic DNA (RAPD) fingerprinting, and examination of adhesion to Caco-2 cells, hydrophobicity, autoaggregation, and in vitro gastrointestinal tolerance. Anti-SpaA specifically reacted with three pLR strains of 25 test strains, as assessed by western blotting, immunofluorescence flow cytometry, and immunoelectron microscopy (IEM) assays. The optimized MRS agar separation plus anti-SpaA-based CIB procedure could quantitatively detect $2.5{\times}10^3CFU/ml$ of pLR colonies spiked in $10^6CFU/ml$ of background bacteria. Eight pLR strains were identified in 124 human fecal samples, and were confirmed by 16S RNA gene sequencing and IEM identification. RAPD fingerprinting of the pLR strains revealed seven different patterns, of which only two isolates from infants showed the same RAPD profiles with LGG. Strain PLR06 was obtained with high adhesion and autoaggregation activities, hydrophobicity, and gastrointestinal tolerance. Anti-SpaA-based CIB is a rapid and inexpensive method for the preliminary screening of novel adherent L. rhamnosus strains for commercial purposes.