• Korean Journal of Microbiology
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• v.37 no.1
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• pp.49-55
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• 2001

Bacillus anthracis is a gram-positive spore-forming bacterium that causes the disease anthrax. The anthrax toxin contains three components, including the protective antigen (PA), which binds to eucaryotic cell surface receptors and mediates the transport of toxins into the cell. In this study, the entire 2,294-nucleotide protective antigen gene (pag) was sequenced from 4 of B. anthracis strains to identify potential variation in the toxin and to further our understanding of B. anthracis evolution in Korea. Sequence alignment of the entire PA gene from 30 strains representative of the four B. anthracis diversity groups revealed mutations. The mutation of B. anthracis BAK are located adjacent to a highly antigenic region crossing the junction between PA domains 3 and 4 shown to be critical to LF binding. The different mutational combinations observed in this study give rise to 11 PA genotypes and 4PA phenotypes. Three-dimensional analysis of all the amino acid changes (Ala to Val) observed in BAK indicated that these changes are not only close sequentially but also very close in three-dimensional space to the antigenic region importan tfor LF binding. Phylogenetic (cladistic) analysis of the pag corresponded with previous strain grouping based on chromosomal variation, suggesting that plasmid evolution in B. anthracis has occurred with little or no horizontal transfer between the different strains.

• Journal of Sensor Science and Technology
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• v.19 no.4
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• pp.306-312
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• 2010

We have detected deoxynivalenol(DON) using a metal-oxide-semiconductor field-effect-transistor(MOSFET)-based biosensor. The MOSFET-based biosensor is fabricated by a standard complementary metal-oxide-semiconductor(CMOS) process, and the biosensor's electrical characteristics were investigated. The output of the sensor was stabilized by employing a reference electrode that applies a fixed bias to the gate. Au which has a chemical affinity for thiol was used as the gate metal to immobilize a self-assembled monolayer(SAM) made of 16-mercaptohexadecanoic acid(MHDA). The SAM was used to immobilize anti-deoxynivalenol antibody. The carboxyl group of the SAM was bound to the anti- deoxynivalenol antibody. Anti-deoxynivalenol antibody and deoxynivalenol were bound by an antigen-antibody reaction. In this study, it is confirmed that the MOSFET-based biosensor can detect deoxynivalenol at concentrations as low as 0.1 ${\mu}g$/ml. The measurements were performed in phosphate buffered saline(PBS; pH 7.4) solution. To verify the interaction among the SAM, antibody, and antigen, surface plasmon resonance(SPR) measurements were performed.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.148-156
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• 2021

Single-chain antibodies against epidermal growth factor receptor variant III (EGFRvIII) are potentially promising agents for developing antibody-based cancer treatment strategies. We described in our previous study the successful expression of an anti-EGFRvIII scFv antibody in Escherichia coli. However, we could also observe the formation of insoluble aggregates in the periplasmic space, limiting the production yield of the active product. In the present study, we investigated the mechanisms by which growth conditions could affect the expression of the soluble anti-EGFRvIII scFv antibody in small-scale E. coli NiCo21(DE3) cultures, attempting to maximize production. The secreted scFv molecules were purified using Ni-NTA magnetic beads and protein characterization was performed using SDS-PAGE and western blot analyses. We used the ImageJ software for protein quantification and determined the antigen-binding activity of the scFv antibody against the EGFRvIII protein. Our results showed that the highest percentage of soluble scFv expression could be achieved under culture conditions that combined low IPTG concentration (0.1 mM), low growth temperature (18℃), and large culture dish surface area. We found moderate-yield soluble scFv production in the culture medium after lactose-mediated induction, which was also beneficial for downstream protein processing. These findings were confirmed by conducting western blot analysis, indicating that the soluble, approximately 30-kDa scFv molecule was localized in the periplasm and the extracellular space. Moreover, the antigen-binding assay confirmed the scFv affinity against the EGFRvIII antigen. In conclusion, our study reveals that low-speed protein expression is preferable to obtain more soluble anti-EGFRvIII scFv protein in an E. coli expression system.

• Journal of Digestive Cancer Research
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• v.4 no.1
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• pp.32-35
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• 2016

Pseudomyxoma peritonei (PMP) is a rare clinical syndrome characterized by profuse jelatinous materials in the abdominal cavity and pelvis with mucinous implants on the peritoneal surface. There are some studies for serum tumor markers, including carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9) and carbohydrate antigen 125 (CA125), to assess the risk of recurrence following cytoreductive surgery and intraperitoneal chemotherapy. However, rare cases were reported about recurrence with increasing serum CEA levels. Herein, we report a case of recurrence of PMP according to serially elevated serum CEA.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.2
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• pp.112-116
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• 2003

An immunosensor based on surface plasmon resonance (SPR) onto a protein G layer by Self-assembly technique was developed for detection of Legionella pneumophila. The protein G layer by self-assembly technique was fabricated on a gold (Au) surface by adsorbing the 11-mercaptoundecanoic acid (MUA) and an activation process for the chemical binding of the free amino (-NH$_2$) of protein G and 11-(MUA) using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDAC) in series. The formation of the protein G layer by self-assembly technique on the Au Substrate and the binding of the antibody and antigen in series were confirmed by SPR spectroscopy. The Surface topographies of the fabricated thin films on an Au substrate were also analyzed by using an atomic force microscope (AFM). Consequently, an immunosensor for the detection of L. pneumophila using SPR was developed with a detection limit of up to 10$^2$CFU per mL.

• Parasites, Hosts and Diseases
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• v.45 no.1 s.141
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• pp.59-63
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• 2007

Merozoite surface protein-1(MSP-1) and merozoite surface protein-2(MSP-2) were used to develop vaccines and to investigate the genetic diversity in Plasmodium falciparum malaria in Iran. Nested polymerase chain reaction amplification was used to determine polymorph isms of block 2 of the MSP-1 and the central domain of MSP-2 genes. A total of 67 microscopically positive P. falciparum infected individuals from a major endemic region, southeast Iran, were included in this trial. Nine alleles of MSP-1 and 11 alleles of MSP-2 were identified. The results showed that amplified product from these surface antigen genes varied in size and there was specific pattern for each isolate. Besides, regarding this pattern, 23 multiple infections with at least 2 alleles were observed. While the endemic regions of malaria in Iran is classified in low to moderate group, but extensive polymorphism was observed for each marker and the MSP-2 central repeat was the most diverse that could be considered in designing malaria vaccine.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.780-786
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• 2002

An immunosensor based on surface plasmon resonance (SPR) with a self-assembled protein G layer was developed for the detection of Escherichia coli O157:H7. A self-assembled protein C layer on a gold (Au) surface was fabricated by adsorbing the mixture of 11-mercaptoundecanoic acid (MUA) and hexanethiol at various molar ratios and by activating chemical binding between free amine (-$NH_2$) of protein G and 11-(MUA) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC) in series. The formation of a self-assembled protein G layer on an Au substrate and the binding of the antibody and antigen in series were confirmed by SPR spectroscopy. The surface morphology analyses of the self-assembled protein G layer on the Au substrate, monoclonal antibody (Mab) against E. coli O157:H7 which was immobilized on protein G, and bound E. coli O157:H7 extracts on Immobilized Mab against E. coii O157:H7 were performed by atomic force microscopy (AFM). The detection limit of the SPR-based immunosensor for E. coli O157:H7 was found to be about $10^4$ cells/ml.

• Parasites, Hosts and Diseases
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• v.38 no.4
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• pp.245-249
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• 2000

A total of 492 cattle sera was screened by IgG-ELISA against Neospora caninum (Nc-1 strain and a Korean isolate, KBA-2) and Toxoplasna gondii. Out of 492, 113 sera (23.0%) reacted positively to either Nc-1 or KBA-2 strains of N. caninum. Among the 113 positive sera, 92 sera (81.4%) reacted with antigens of both strains, but 6 sera (5.3%) with Nc-1 and 15 sera (13.3%) with KBA-2 strain only And with T. gondii antigen, 6 sera (1.2%) were positive but all reacted with N. caninum antigen also. Western blot revealed typical binding pattern according to ELISA values, such that high OD group reacted specifically to the major surface proteins including 43 kDa protein. Seroprevalence of 23.0% indicates that neosporosis seemed to be one of major causes of abortion in cattle. It is suggested here to establish more epidemiological researches nationwide systematically.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5463-5467
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• 2012

Hepatitis B virus (HBV) infection is contagious with transmissiobn vertically or horizontally by blood products and body secretions. Over 50% of Iranian carriers contracted the infection prenatally, making this the most likely route of transmission of HBV in Iran. To evaluate the resistance to adefovir (ADV) therapy in patients with chronic hepatitis B infection, a study was conducted on 70 patients (63 males and 7 females), who had received in first line lamivudine and second line adefovir. All were tested for the presence of hepatitis B surface antigen (HBsAg), hepatitis B envelope antigen (HBeAg), serum alanine amino transferase (ALT) level and HBV DNA load before and after treatment with ADV. In all samples, resistance to lamivudine and ADV was tested with real time PCR. Among seventy patients with chronic hepatitis B infection, 18 (25.7%) were resistant to LAM and 8 (11.4%) were resistant to ADV. Only one patient was negative for the presence of HBS-Ag (5.6%) and two were negative for HBe-Ag (11.1%). In this study we used a new method (ALLGIO probe assay) that has high sensitivity in detection of adefovir resistance mutants, which we recommend to other researchers. Mutant strains of the YMDD motif of HBV polymerase can be found in some patients under treatment with lamivudine and ADV. ADV has been demonstrated to be efficient in patients with lamivudine resistant HBV.

• Korean Journal of Veterinary Research
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• v.37 no.4
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• pp.825-829
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• 1997

The spleen and placenta from the aborted fetuses as well as lymphnodes and placenta of the corresponding dams naturally infected with T sergenti were used to localize the parasite antigens by immunohistochemical staining for the possible congenital transmission of theileriosis. Parasite-specific antigens were detected immunohistochemically by incubating the sections with specific monoclonal antibody prepared against 34KD surface antigen of T sergenti and visualized via the avidin biotin complex(ABC) method. Specific T sergenti antigen was detected in the sections of formalin or acetone-fixed fetal spleens and placenta. Similar antigens were also demonstrated in lymphnodes and placentas of the corresponding dams. It is concluded that this technique will eventually play an important role in specialized diagnostic laboratories in the verification/evaluation of congenital infection with T sergenti.