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122 results on '"Sirawaraporn, Worachart"'

5. Cloning and expression of Mycobacterium tuberculosis and Mycobacterium leprae dihydropteroate synthase in Escherichia coli

Author

Nopponpunth, Vanida, Sirawaraporn, Worachart, Greene, Patricia J., and Santi, Daniel V.

Subjects
Tuberculosis -- Research, Microbial enzymes -- Analysis, Sulfonamides -- Research, Dapsone -- Research, Biological sciences
Abstract

Research was conducted on cloning, expression and purification of dihydropteroate synthases from two speices of Mycobacteria. Results show the enzymes are under the control of T5 promoter, have a molecular mass of approximately 60 kDa, exist as dimers with two identical subunits and are inhibited by sulfonamides and dapsone.

Published
1999

10. Homology building as a means to define antigenic epitopes on dihydrofolate reductase (DHFR) from Plasmodium falciparum

Author

Chen Ming, Weng Jimmy E, Rønn Anita M, Jørgensen Flemming S, Christensen Inge T, Alifrangis Michael, Bygbjerg Ib C, Sirawaraporn Worachart, Palarasah Yaseelan, and Koch Claus

Subjects
Arctic medicine. Tropical medicine, RC955-962, Infectious and parasitic diseases, RC109-216
Abstract

Abstract Background The aim of this study was to develop site-specific antibodies as a tool to capture Plasmodium falciparum-dihydrofolate reductase (Pf-DHFR) from blood samples from P. falciparum infected individuals in order to detect, in a sandwich ELISA, structural alterations due to point mutations in the gene coding for Pf-DHFR. Furthermore, we wanted to study the potential use of homology models in general and of Pf-DHFR in particular in predicting antigenic malarial surface epitopes. Methods A homology model of Pf-DHFR domain was employed to define an epitope for the development of site-specific antibodies against Pf-DHFR. The homology model suggested an exposed loop encompassing amino acid residues 64–100. A synthetic peptide of 37-mers whose sequence corresponded to the sequence of amino acid residues 64–100 of Pf-DHFR was synthesized and used to immunize mice for antibodies. Additionally, polyclonal antibodies recognizing a recombinant DHFR enzyme were produced in rabbits. Results and conclusions Serum from mice immunized with the 37-mer showed strong reactivity against both the immunizing peptide, recombinant DHFR and a preparation of crude antigen from P. falciparum infected red blood cells. Five monoclonal antibodies were obtained, one of which showed reactivity towards crude antigen prepared from P. falciparum infected red cells. Western blot analysis revealed that both the polyclonal and monoclonal antibodies recognized Pf-DHFR. Our study provides insight into the potential use of homology models in general and of Pf-DHFR in particular in predicting antigenic malarial surface epitopes.

Published
2004
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12. Development and evaluation of an immunochromatographic assay to detect serum anti-leptospiral lipopolysaccharide IgM in acute leptospirosis

Author

Doungchawee, Galayanee, primary, Sutdan, Direk, additional, Niwatayakul, Kannika, additional, Inwisai, Tasanee, additional, Sitthipunya, Athisri, additional, Boonsathorn, Naphatsawan, additional, Sakulterdkiat, Titipatima, additional, Sirawaraporn, Worachart, additional, and Thongboonkerd, Visith, additional

Published
2017
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13. Cheaper faster drug development validated by the repositioning of drugs against neglected tropical diseases

Author

Williams, Kevin, Bilsland, Elizabeth, Sparkes, Andrew, Aubrey, Wayne, Young, Michael, Soldatova, Larisa N, De Grave, Kurt, Ramon, Jan, de Clare, Michaela, Sirawaraporn, Worachart, Oliver, Stephen G, and King, Ross D

Subjects
Artificial intelligence, drug design, Drug Evaluation, Preclinical, Quantitative Structure-Activity Relationship, Antineoplastic Agents, quantitative structure activity relationship, Drug design, Automation, Rare Diseases, Tropical Medicine, Malaria, Vivax, Humans, Technology, Pharmaceutical, Research Articles, Models, Statistical, Drug Repositioning, Reproducibility of Results, artificial intelligence, Quantitative structure activity relationship, Regression Analysis, Plasmodium vivax, Algorithms, Software
Abstract

There is an urgent need to make drug discovery cheaper and faster. This will enable the development of treatments for diseases currently neglected for economic reasons, such as tropical and orphan diseases, and generally increase the supply of new drugs. Here we report the Robot Scientist “Eve” designed to make drug discovery more economical. A Robot Scientist is a laboratory automation system that uses artificial intelligence (AI) techniques to discover scientific knowledge through cycles of experimentation. Eve integrates and automates library screening, hit confirmation, and lead generation through Quantitative Structure Activity Relationship (QSAR) learning and testing. Using econometric modelling we demonstrate that the use of AI to select compounds economically outperforms standard drug screening. For further efficiency Eve utilizes a standardized form of assay to compute Boolean functions of compound properties. These assays can be quickly and cheaply engineered using synthetic biology, enabling more targets to be assayed for a given budget. Eve has repositioned several drugs against specific targets in parasites that cause tropical diseases. One validated discovery is that the anti-cancer compound TNP-470 is a potent inhibitor of dihydrofolate reductase in the malaria-causing parasite Plasmodium vivax. ispartof: Journal of the Royal Society Interface vol:12 issue:104 ispartof: location:England status: published

Published
2015

23. Inhibitors of Multiple Mutants of Plasmodium falciparum Dihydrofolate Reductase and Their Antimalarial Activities

Author

Kamchonwongpaisan, Sumalee, primary, Quarrell, Rachel, additional, Charoensetakul, Netnapa, additional, Ponsinet, Rachel, additional, Vilaivan, Tirayut, additional, Vanichtanankul, Jarunee, additional, Tarnchompoo, Bongkoch, additional, Sirawaraporn, Worachart, additional, Lowe, Gordon, additional, and Yuthavong, Yongyuth, additional

Published
2003
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30. Development of 2,4-Diaminopyrimidines as Antimalarials Based on Inhibition of the S108N and C59R+S108N Mutants of Dihydrofolate Reductase from Pyrimethamine-Resistant Plasmodium falciparum

Author

Tarnchompoo, Bongkoch, primary, Sirichaiwat, Chawanee, additional, Phupong, Worrapong, additional, Intaraudom, Chakapong, additional, Sirawaraporn, Worachart, additional, Kamchonwongpaisan, Sumalee, additional, Vanichtanankul, Jarunee, additional, Thebtaranonth, Yodhathai, additional, and Yuthavong, Yongyuth, additional

Published
2002
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34. Interaction of pyrimethamine, cycloguanil, WR99210 and their analogues with Plasmodium falciparum dihydrofolate reductase: structural basis of antifolate resistance

Author

Rastelli, Giulio, primary, Sirawaraporn, Worachart, additional, Sompornpisut, Pornthep, additional, Vilaivan, Tirayut, additional, Kamchonwongpaisan, Sumalee, additional, Quarrell, Rachel, additional, Lowe, Gordon, additional, Thebtaranonth, Yodhathai, additional, and Yuthavong, Yongyuth, additional

Published
2000
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38. Safety and immunogenicity of REMUNE™ in HIV-infected Thai subjects

Author

Limsuwan, Anuwat, primary, Churdboonchart, Vina, additional, Moss, Ronald B., additional, Sirawaraporn, Worachart, additional, Sutthent, Reungpung, additional, Smutharaks, Buranaj, additional, Glidden, David, additional, Trauger, Richard, additional, Theofan, Georgia, additional, and Carlo, Dennis, additional

Published
1998
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42. Antfolate resistance in malaria

Author

Daniel V. Santi and Sirawaraporn Worachart

Subjects
Infectious Diseases, Resistance (ecology), business.industry, medicine, Parasitology, medicine.disease, business, Virology, Malaria
Published
1998

43. Recent Advance on Thymidylate Synthase-Dihydrofolate Reductase from Plasmodium falciparum.

Author

Mongkolsuk, S., Lovett, P. S., Trempy, J. E., and Sirawaraporn, Worachart

Abstract

The coding sequence of bifunctional thymidylate synthase-dihydrofolate reductase (TS-DHFR) from moderate pyrimethamine resistant strain of Plasmodium falciparum was assembled in a pUC expression vector. Insertion of a synthetic oligonucleotide duplex containing a ribosomal binding sequence at 5' upstream to ATG start codon resulted in a recombinant plasmid which expressed catalytically active TS-DHFR in E. coli. The expression of Plasmodium enzyme was demonstrated as follows: First, transformation of a TS-deficient E. coli resulted in genetic complementation of the deficiency and the activities of TS and DHFR were significantly higher than those in control host extracts. Second, TS and DHFR activities copurified upon chromatography with an apparent molecular weight ∼ 110 kDa, a characteristic of protozoan bifunctional enzyme. Third, the enzyme formed a covalent complex with [3H] FdUMP-CH2H4folate, and SDS polyacrylamide gel electrophoresis showed the subunit of the recombinant enzyme to be 67 kDa. Finally, N-terminus sequencing of the 67 kDa protein indicated that the N-terminus was not blocked and the sequences of the first 10 amino acids perfectly matched the reported nucleotide sequence. The recombinant enzyme was purified to homogeneity using 10 formylfolate affinity chromatography followed by FPLC on Mono Q column. Since the coding sequence possesses unique Nco1 and Xba1 sites which flank 243 bp of the DHFR gene that include point mutations thus far linked to pyrimethamine resistance, recombinant plasmids of wild type (3D7) and highly pyrimethamine resistant (7G8) gene were constructed by cassette mutagenesis using Nco1 -Xba1 fragments from the corresponding cloned TS-DHFR genes. Characterization of the purified-recombinant enzymes with regard to their kinetic properties and inhibition by pyrimethamine strongly clearly indicated that point mutations are the molecular basis of pyrimethamine resistance in P. falciparum. [ABSTRACT FROM AUTHOR]

Published
1992
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44. Preparation of Blotted Membrane for Protein Microsequencing.

Author

Walker, John M., Hyde, John E., and Sirawaraporn, Worachart

Abstract

This chapter aims to provide a step-by-step procedure in preparing protein samples of limited quantities for partial sequence analysis. Its content will cover a brief introduction on various types of sequenators thus far developed, with the emphasis on the latest technology of gas-liquid-phase sequenator. Detailed descriptions will be focused on how to electroblot protein samples onto polyvinylidene fluoride (PVDF) membrane. The method enables the beginner to prepare protein blots properly for direct microsequencing using currently available automated gas-liquid-phase sequenators. [ABSTRACT FROM AUTHOR]

Published
1993
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48. Homology building as a means to define antigenic epitopes on dihydrofolate reductase (DHFR) from Plasmodium falciparum.

Author

Alifrangis, Michael, Christensen, Inge T., Jørgensen, Flemming S., Rønn, Anita M., Weng, Jimmy E., Ming Chen, Bygbjerg, Ib C., Sirawaraporn, Worachart, Palarasah, Yaseelan, and Koch, Claus

Subjects
PLASMODIUM falciparum, AMINO acids, MALARIA, IMMUNOGLOBULINS, EPITOPES, SERUM, MONOCLONAL antibodies
Abstract

Background: The aim of this study was to develop site-specific antibodies as a tool to capture Plasmodium falciparum-dihydrofolate reductase (Pf-DHFR) from blood samples from P. falciparum infected individuals in order to detect, in a sandwich ELISA, structural alterations due to point mutations in the gene coding for Pf-DHFR. Furthermore, we wanted to study the potential use of homology models in general and of Pf-DHFR in particular in predicting antigenic malarial surface epitopes. Methods: A homology model of Pf-DHFR domain was employed to define an epitope for the development of site-specific antibodies against Pf-DHFR. The homology model suggested an exposed loop encompassing amino acid residues 64-100. A synthetic peptide of 37-mers whose sequence corresponded to the sequence of amino acid residues 64-100 of Pf-DHFR was synthesized and used to immunize mice for antibodies. Additionally, polyclonal antibodies recognizing a recombinant DHFR enzyme were produced in rabbits. Results and conclusions: Serum from mice immunized with the 37-mer showed strong reactivity against both the immunizing peptide, recombinant DHFR and a preparation of crude antigen from P. falciparum infected red blood cells. Five monoclonal antibodies were obtained, one of which showed reactivity towards crude antigen prepared from P. falciparum infected red cells. Western blot analysis revealed that both the polyclonal and monoclonal antibodies recognized Pf-DHFR. Our study provides insight into the potential use of homology models in general and of Pf-DHFR in particular in predicting antigenic malarial surface epitopes. [ABSTRACT FROM AUTHOR]

Published
2004
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49. Insights into antifolate resistance from malarial DHFR-TS structures.

Author

Yuvaniyama, Jirundon, Chitnumsub, Penchit, Kamchonwongpaisan, Sumalee, Vanichtanankul, Jarunee, Sirawaraporn, Worachart, Taylor, Paul, Walkinshaw, Malcolm D., and Yuthavong, Yongyuth

Subjects
PLASMODIUM falciparum, ANTIMALARIALS, DRUG resistance
Abstract

Plasmodium falciparum dihydrofolate reductase-thymidylate synthase (PfDHFR-TS) is an important target of antimalarial drugs. The efficacy of this class of DHFR-inhibitor drugs is now compromised because of mutations that prevent drug binding yet retain enzyme activity. The crystal structures of PfDHFR-TS from the wild type (TM4/8.2) and the quadruple drug-resistant mutant (V1/S) strains, in complex with a potent inhibitor WR99210, as well as the resistant double mutant (K1 CB1) with the antimalarial pyrimethamine, reveal features for overcoming resistance. In contrast to pyrimethamine, the flexible side chain of WR99210 can adopt a conformation that fits well in the active site, thereby contributing to binding. The single-chain bifunctional PfDHFR-TS has a helical insert between the DHFR and TS domains that is involved in dimerization and domain organization. Moreover, positively charged grooves on the surface of the dimer suggest a function in channeling of substrate from TS to DHFR active sites. These features provide possible approaches for the design of new drugs to overcome antifolate resistance. [ABSTRACT FROM AUTHOR]

Published
2003
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