The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
Mehmet Ozsoz - One of the best experts on this subject based on the ideXlab platform.
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electrochemical biosensor for the interaction of dna with the alkylating agent 4 4 dihydroxy chalcone based on guanine and adenine signals
Journal of Pharmaceutical and Biomedical Analysis, 2002Co-Authors: Burcu Meric, Kagan Kerman, Dilsat Ozkan, Pinar Kara, Arzum Erdem, Ozlem Kucukoglu, Ercin Erciyas, Mehmet OzsozAbstract:The interaction of an alkylating agent, 4,4'-dihydroxy chalcone (DHC) with calf thymus double stranded DNA (dsDNA) and calf thymus single stranded DNA (ssDNA) was studied electrochemically based on the oxidation signals of guanine and adenine by using differential pulse voltammetry (DPV) at carbon paste electrode (CPE). As a result of the alkylation of DHC between the base pairs in dsDNA, the voltammetric signal of guanine and adenine greatly decreased. After the interaction of DHC with ssDNA, a higher decrease in the oxidation signals of guanine and adenine was observed under the same conditions. The partition coefficients of DHC at dsDNA and ssDNA modified CPEs were calculated. The interactions of DHC with synthetic polynucleotides, such as Polyguanylic Acid and polyadenylic Acid were also observed. In addition, the detection limit and the reproducibility were determined by using DPV. The interaction of DHC with dsDNA in solution-phase was also investigated and the results were compared with the ones obtained by surface immobilized dsDNA. The application of electrochemical DNA biosensor for monitoring the DNA-alkylating agent interactions was explored.
Hiroyuki Itabe - One of the best experts on this subject based on the ideXlab platform.
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The membrane-type collectin CL-P1 is a scavenger receptor on vascular endothelial cells.
Journal of Biological Chemistry, 2001Co-Authors: Katsuki Ohtani, Tetsuo Kase, Hiroyuki Keshi, Yoshinori Sakai, Atsushi Fukuoh, Yasuhiko Suzuki, Takao Kawai, Takashi Sakamoto, Hiroyuki ItabeAbstract:Abstract Collectins are a family of C-type lectins that have collagen-like sequences and carbohydrate recognition domains (CRD). They are involved in host defense through their ability to bind to carbohydrate antigens of microorganisms. The scavenger receptors type A and MARCO are classical type scavenger receptors that have internal collagen-like domains. Here we describe a new scavenger receptor that is a membrane-type collectin from placenta (collectin placenta 1 (CL-P1)), which has a typical collectin collagen-like domain and a CRD. The cDNA has an insert of about 2.2 kilobases coding for a protein containing 742 amino Acid residues. The deduced amino Acid sequence shows that CL-P1 is a type II membrane protein, has a coiled-coil region, a collagen-like domain, and a CRD. It resembles type A scavenger receptors because the scavenger receptor cysteine-rich domain is replaced by a CRD. Northern analyses, reverse transcription-polymerase chain reaction, and immunohistochemistry show that CL-P1 is expressed in vascular endothelial cells but not in macrophages. By immunoblotting and flow cytometry CL-P1 appears to be a membrane glycoprotein of about 140 kDa in human umbilical vein or arterial endothelial cells, placental membrane extracts, and CL-P1 transfected Chinese hamster ovary cells. We found that CL-P1 can bind and phagocytose not only bacteria (Escherichia coli and Staphylococcus aureus) but also yeast (Saccharomyces cerevisiae). Furthermore, it reacts with oxidized low density lipoprotein (OxLDL) but not with acetylated LDL (AcLDL). These binding activities are inhibited by polyanionic ligands (polyinosinic Acid, Polyguanylic Acid, dextran sulfate) and OxLDL but not by polycationic ligands (polyadenylic Acid or polycytidylic Acid), LDL, or AcLDL. These results indicate that CL-P1 might play important roles in host defenses that are different from those of soluble collectins in innate immunity.
Ana Maria Oliveirabrett - One of the best experts on this subject based on the ideXlab platform.
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atomic force microscopy and voltammetric investigation of quadruplex formation between a triazole acridine conjugate and guanine containing repeat dna sequences
Analytical Chemistry, 2015Co-Authors: Anamaria Chiorceapaquim, Ana Dora Rodrigues Pontinha, Ramon Eritja, Genny Lucarelli, Silvia Sparapani, Stephen Neidle, Ana Maria OliveirabrettAbstract:The interactions of the Tetrahymena telomeric repeat sequence d(TG4T) and the Polyguanylic Acid (poly(G)) sequence with the quadruplex-targeting triazole-linked acridine ligand GL15 were investigated using atomic force microscopy (AFM) at a highly oriented pyrolytic graphite and voltammetry at a glassy carbon electrode. GL15 interacted with both sequences, in a time dependent manner, and G-quadruplex formation was detected. AFM showed the adsorption of quadruplexes as small d(TG4T) and poly(G) spherical aggregates and large quadruplex-based poly(G) assemblies, and voltammetry showed the decrease and disappearance of GL15 and guanine oxidation peak currents and appearance of the G-quadruplex oxidation peak. The GL15 molecule strongly stabilized and accelerated G-quadruplex formation in both Na+ and K+ ion-containing solution, although only K+ promoted the formation of perfectly aligned tetra-molecular G-quadruplexes. The small-molecule complex with the d(TG4T) quadruplex is discrete and approximately globu...
Burcu Meric - One of the best experts on this subject based on the ideXlab platform.
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electrochemical biosensor for the interaction of dna with the alkylating agent 4 4 dihydroxy chalcone based on guanine and adenine signals
Journal of Pharmaceutical and Biomedical Analysis, 2002Co-Authors: Burcu Meric, Kagan Kerman, Dilsat Ozkan, Pinar Kara, Arzum Erdem, Ozlem Kucukoglu, Ercin Erciyas, Mehmet OzsozAbstract:The interaction of an alkylating agent, 4,4'-dihydroxy chalcone (DHC) with calf thymus double stranded DNA (dsDNA) and calf thymus single stranded DNA (ssDNA) was studied electrochemically based on the oxidation signals of guanine and adenine by using differential pulse voltammetry (DPV) at carbon paste electrode (CPE). As a result of the alkylation of DHC between the base pairs in dsDNA, the voltammetric signal of guanine and adenine greatly decreased. After the interaction of DHC with ssDNA, a higher decrease in the oxidation signals of guanine and adenine was observed under the same conditions. The partition coefficients of DHC at dsDNA and ssDNA modified CPEs were calculated. The interactions of DHC with synthetic polynucleotides, such as Polyguanylic Acid and polyadenylic Acid were also observed. In addition, the detection limit and the reproducibility were determined by using DPV. The interaction of DHC with dsDNA in solution-phase was also investigated and the results were compared with the ones obtained by surface immobilized dsDNA. The application of electrochemical DNA biosensor for monitoring the DNA-alkylating agent interactions was explored.
Katsuki Ohtani - One of the best experts on this subject based on the ideXlab platform.
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The membrane-type collectin CL-P1 is a scavenger receptor on vascular endothelial cells.
Journal of Biological Chemistry, 2001Co-Authors: Katsuki Ohtani, Tetsuo Kase, Hiroyuki Keshi, Yoshinori Sakai, Atsushi Fukuoh, Yasuhiko Suzuki, Takao Kawai, Takashi Sakamoto, Hiroyuki ItabeAbstract:Abstract Collectins are a family of C-type lectins that have collagen-like sequences and carbohydrate recognition domains (CRD). They are involved in host defense through their ability to bind to carbohydrate antigens of microorganisms. The scavenger receptors type A and MARCO are classical type scavenger receptors that have internal collagen-like domains. Here we describe a new scavenger receptor that is a membrane-type collectin from placenta (collectin placenta 1 (CL-P1)), which has a typical collectin collagen-like domain and a CRD. The cDNA has an insert of about 2.2 kilobases coding for a protein containing 742 amino Acid residues. The deduced amino Acid sequence shows that CL-P1 is a type II membrane protein, has a coiled-coil region, a collagen-like domain, and a CRD. It resembles type A scavenger receptors because the scavenger receptor cysteine-rich domain is replaced by a CRD. Northern analyses, reverse transcription-polymerase chain reaction, and immunohistochemistry show that CL-P1 is expressed in vascular endothelial cells but not in macrophages. By immunoblotting and flow cytometry CL-P1 appears to be a membrane glycoprotein of about 140 kDa in human umbilical vein or arterial endothelial cells, placental membrane extracts, and CL-P1 transfected Chinese hamster ovary cells. We found that CL-P1 can bind and phagocytose not only bacteria (Escherichia coli and Staphylococcus aureus) but also yeast (Saccharomyces cerevisiae). Furthermore, it reacts with oxidized low density lipoprotein (OxLDL) but not with acetylated LDL (AcLDL). These binding activities are inhibited by polyanionic ligands (polyinosinic Acid, Polyguanylic Acid, dextran sulfate) and OxLDL but not by polycationic ligands (polyadenylic Acid or polycytidylic Acid), LDL, or AcLDL. These results indicate that CL-P1 might play important roles in host defenses that are different from those of soluble collectins in innate immunity.