The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform
Charles Brenner - One of the best experts on this subject based on the ideXlab platform.
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identification of isn1 and sdt1 as glucose and vitamin regulated nicotinamide Mononucleotide and nicotinic acid Mononucleotide 5 nucleotidases responsible for production of nicotinamide riboside and nicotinic acid riboside
Journal of Biological Chemistry, 2009Co-Authors: Katrina L. Bogan, Peter Belenky, Charles R. Evans, Peng Song, Charles F. Burant, Robert T. Kennedy, Charles BrennerAbstract:Recently, we discovered that nicotinamide riboside and nicotinic acid riboside are biosynthetic precursors of NAD(+), which are utilized through two pathways consisting of distinct enzymes. In addition, we have shown that exogenously supplied nicotinamide riboside is imported into yeast cells by a dedicated transporter, and it extends replicative lifespan on high glucose medium. Here, we show that nicotinamide riboside and nicotinic acid riboside are authentic intracellular metabolites in yeast. Secreted nicotinamide riboside was detected with a biological assay, and intracellular levels of nicotinamide riboside, nicotinic acid riboside, and other NAD(+) metabolites were determined by a liquid chromatography-mass spectrometry method. A biochemical genomic screen indicated that three yeast enzymes possess nicotinamide Mononucleotide 5'-nucleotidase activity in vitro. Metabolic profiling of knock-out mutants established that Isn1 and Sdt1 are responsible for production of nicotinamide riboside and nicotinic acid riboside in cells. Isn1, initially classified as an IMP-specific 5'-nucleotidase, and Sdt1, initially classified as a pyrimidine 5'-nucleotidase, are additionally responsible for dephosphorylation of pyridine Mononucleotides. Sdt1 overexpression is growth-inhibitory to cells in a manner that depends on its active site and correlates with reduced cellular NAD(+). Expression of Isn1 protein is positively regulated by the availability of nicotinic acid and glucose. These results reveal unanticipated and highly regulated steps in NAD(+) metabolism.
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Identification of Isn1 and Sdt1 as Glucose- and Vitamin-regulated Nicotinamide Mononucleotide and Nicotinic Acid Mononucleotide 5′-Nucleotidases Responsible for Production of Nicotinamide Riboside and Nicotinic Acid Riboside
The Journal of biological chemistry, 2009Co-Authors: Katrina L. Bogan, Peter Belenky, Charles R. Evans, Peng Song, Charles F. Burant, Robert T. Kennedy, Charles BrennerAbstract:Recently, we discovered that nicotinamide riboside and nicotinic acid riboside are biosynthetic precursors of NAD(+), which are utilized through two pathways consisting of distinct enzymes. In addition, we have shown that exogenously supplied nicotinamide riboside is imported into yeast cells by a dedicated transporter, and it extends replicative lifespan on high glucose medium. Here, we show that nicotinamide riboside and nicotinic acid riboside are authentic intracellular metabolites in yeast. Secreted nicotinamide riboside was detected with a biological assay, and intracellular levels of nicotinamide riboside, nicotinic acid riboside, and other NAD(+) metabolites were determined by a liquid chromatography-mass spectrometry method. A biochemical genomic screen indicated that three yeast enzymes possess nicotinamide Mononucleotide 5'-nucleotidase activity in vitro. Metabolic profiling of knock-out mutants established that Isn1 and Sdt1 are responsible for production of nicotinamide riboside and nicotinic acid riboside in cells. Isn1, initially classified as an IMP-specific 5'-nucleotidase, and Sdt1, initially classified as a pyrimidine 5'-nucleotidase, are additionally responsible for dephosphorylation of pyridine Mononucleotides. Sdt1 overexpression is growth-inhibitory to cells in a manner that depends on its active site and correlates with reduced cellular NAD(+). Expression of Isn1 protein is positively regulated by the availability of nicotinic acid and glucose. These results reveal unanticipated and highly regulated steps in NAD(+) metabolism.
Steven G. Newmaster - One of the best experts on this subject based on the ideXlab platform.
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improving sequencing quality from pcr products containing long Mononucleotide repeats
BioTechniques, 2010Co-Authors: Aron J. Fazekas, Royce Steeves, Steven G. NewmasterAbstract:Stutter products are a common artifact in the PCR amplification of frequently used genetic markers that contain Mononucleotide simple sequence repeats. Despite the importance of accurate determination of nucleotide sequence and allele size, there has been little progress toward decreasing the formation of stutter products during PCR. In this study, we tested the effects of lowered extension temperatures, inclusion of co-solutes in PCR, PCR cycle number, and the use of different polymerases on sequence quality for a set of sequences containing Mononucleotide A/T repeats of 10-17 bp. Our analyses showed that sequence quality of Mononucleotide repeats
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Improving sequencing quality from PCR products containing long Mononucleotide repeats.
BioTechniques, 2010Co-Authors: Aron J. Fazekas, Royce Steeves, Steven G. NewmasterAbstract:Stutter products are a common artifact in the PCR amplification of frequently used genetic markers that contain Mononucleotide simple sequence repeats. Despite the importance of accurate determination of nucleotide sequence and allele size, there has been little progress toward decreasing the formation of stutter products during PCR. In this study, we tested the effects of lowered extension temperatures, inclusion of co-solutes in PCR, PCR cycle number, and the use of different polymerases on sequence quality for a set of sequences containing Mononucleotide A/T repeats of 10-17 bp. Our analyses showed that sequence quality of Mononucleotide repeats
Shihe Yang - One of the best experts on this subject based on the ideXlab platform.
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Quantitative analysis of Mononucleotides by isotopic labeling surface-enhanced Raman scattering spectroscopy.
Biosensors & bioelectronics, 2011Co-Authors: Penggang Yin, Li Jiang, Xiufeng Lang, Lin Guo, Shihe YangAbstract:A novel surface-enhanced Raman scattering (SERS) approach for accurate quantification of Mononucleotides of deoxyribonucleic acid (DNA) is described. Reproducible SERS measurement was achieved by using isotopically labeled internal standard. By measuring the SERS spectra of Mononucleotides and its isotope internal standard in combination with multivariate data analysis, the method was successfully applied to quantify Mononucleotides. The independent validation of analyte concentrations gave a standard deviation of within 2%, which is comparable to HPLC result. Finally, a mixture of four Mononucleotides of DNA was prepared to explore the possibility of quantifying the concentration of label-free, sequence-specific DNA strands by this approach. As compared to liquid chromatography/mass spectrometry (LC/MS), our method can be similarly precise but the SERS measurement is simple, rapid and potentially cheap.
Narayana M. S. Sirimuthu - One of the best experts on this subject based on the ideXlab platform.
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Surface-enhanced Raman spectroscopy (SERS) for sub-micromolar detection of DNA/RNA Mononucleotides.
Journal of the American Chemical Society, 2006Co-Authors: Steven E. J. Bell, Narayana M. S. SirimuthuAbstract:Surface-enhanced Raman (SER) spectra of all the DNA/RNA Mononucleotides have been obtained with high sensitivity using citrate-reduced silver colloids aggregated with MgSO4, rather than the more usual halide ions, which were found to prevent enhancement of these compounds. The SERS spectra of adenine, guanine, thymine, cytosine, and uracil were recorded along with their corresponding nucleosides and 5'-deoxynucleotides. For the cytosine series, all three spectra had similar relative band intensities but the spectra of adenine were different from those of adenosine and dAMP, probably due to differences in orientation on the surface. No enhanced bands from the phosphate or sugar groups were observed. There were general similarities between the SERS spectra of the purine Mononucleotides and the pyrimidine Mononucleotides, but the spectra were sufficiently different to allow each of them to be distinguished. This method can therefore be used for high sensitivity, label-free identification of Mononucleotides.
Ivona Matić - One of the best experts on this subject based on the ideXlab platform.
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Adsorption mechanisms of RNA Mononucleotides on silver nanoparticles.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2014Co-Authors: Snežana Miljanić, Adriana Dijanošić, Ivona MatićAbstract:Abstract Surface-enhanced Raman scattering (SERS) of four RNA Mononucleotides (AMP, GMP, CMP and UMP) has been studied on the citrate-reduced silver colloid aggregated with sodium sulfate. Concentration dependent spectra in the range of 1 × 10−7–1 × 10−4 mol dm−3 were obtained, assigned and interpreted according to the surface selection rules. For purine Mononucleotides, AMP and GMP, adsorption onto the silver nanoparticles through the six-membered ring of the nitrogenous base was suggested. Concentration dependent splitting of the ring breathing band in the spectra of AMP indicated coexistence of two species on the silver surface, which differed in contribution of the adenine N1 atom and the exocyclic NH2 group in binding. Unlike the AMP spectra, the spectra of GMP implied only one mode of adsorption of the molecules onto the silver nanoparticles, taking place through the guanine N1H and C O group. Weak SERS spectra of pyrimidine Mononucleotides, CMP and UMP, pointed to involvement of carbonyl oxygen in adsorption process, whereby the molecules adopted the position on the nanoparticles with ribose close to the metal surface. Intense bands in the low wavenumber region, associated with stretching of the formed Ag N and/or Ag O bonds, supported chemical binding of the RNA Mononucleotides with the silver surface.
