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Biomedical subjects

N I Taranenko

Publications and source records attributed to N I Taranenko.

15 recordsLinked to original sources

Matrix-assisted laser desorption/ionization detection of polymerase chain reaction products by utilizing the 5'-3' exonuclease activity of Thermus aquaticus DNA polymerase.

The 5'-3' exonuclease activity of DNA polymerase was utilized in the polymerase chain reaction system to generate a specific signal concomitant with amplification. These signals were detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). This method obviates the need to perform extensive DNA purification of reaction products that is often necessary for detecting larger DNA molecules by mass spectrometry. Oligonucleotides complementary to the internal region of the amplicon are degraded by the 5'-3' exonuclease activity and the degradation products are analyzed by MALDI mass spectrometry. We refer to this assay as the Exo-taq assay or probe degradation assay. This method should be amenable to automation.

DNA↗

Laser desorption mass spectrometry for microbial DNA analysis.

Recently, we demonstrated that a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF MS) can be used to determine the molecular weight of polymerase chain reaction (PCR) products of intact 16S rRNA regions and to profile their restriction digests. This is the first time that MALDI-TOF MS with ultraviolet (UV) photoionization has been used to analyze a PCR product of approximately 1600 nucleotides in length.

DNA, Bacterial↗

Nonresonant MALDI of oligonucleotides: mechanism of ion desorption.

Oligonucleotide ions have been detected using matrix-assisted laser desorption/ionization (MALDI) under nonresonant laser irradiation of the sample. When mass resolution was not limited by adduct attachment to the analyte ions, the nonresonant MALDI spectra demonstrated better resolution than the spectra acquired with resonant ultraviolet irradiation. We found that preparation of thin-film samples on absorbing substrate surfaces was critical for the success of NR-MALDI. The possible acoustic mechanisms of ion formation and desorption are discussed.

Oligonucleotides↗

Detection of trinucleotide expansion in neurodegenerative disease by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Genotyping of the dentatorubral-pallidoluysian atrophy (DRPLA) locus in six patient samples, representing four normal individuals and two DRPLA patients, was successfully obtained using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). DRPLA is a dominantly inherited neurodegenerative disorder associated with the expansion of an unstable trinucleotide (CAG) repeat. The accurate determination of repeat length utilizing MALDI supports the use of this methodology for the analysis of genes containing unstable CAG trinucleotide repeats.

Alleles↗

Sequencing DNA using mass spectrometry for ladder detection.

Sequencing of DNA fragments of 130 and 200 bp using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for DNA ladder detection was demonstrated. With further improvement in mass resolution and detection sensitivity, mass spectrometry shows great promise for routine DNA sequencing in the future.

Bacteriophage lambda↗

Matrix-assisted laser desorption/ionization for short tandem repeat loci.

Matrix-assisted laser desorption/ionization was used for the detection of four base short tandem repeats (STR) for clinical samples using a time-of-flight mass spectrometer. Since STR plays an important role in genetic disease and human identification, this work indicates that laser desorption mass spectrometry has the potential to achieve rapid DNA typing for both forensic applications and genetic disease diagnosis.

DNA↗

Matrix-assisted laser desorption/ionization for sequencing single-stranded and double-stranded DNA.

The DNA sequence of a single-stranded and double-stranded template was determined. The templates were sequenced using the chain termination method and cycle sequencing method and detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The sequencing products were analyzed successfully without the laborious and expensive methods for removal of the template. Direct sequencing of the double-stranded template was achieved with minimal post-reaction purifications, which could be extremely important for mutation analysis and clinical diagnosis. A systematic study of the mechanisms and kinetics of sequencing reactions was also performed. The details of this analysis and directions for future improvements of the quality of sequencing are presented.

Base Sequence↗

The study of 2,3,4-trihydroxyacetophenone and 2,4,6-trihydroxyacetophenone as matrices for DNA detection in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

The matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometric study of DNA detection using 2,3,4-trihydroxyacetophenone, 2,4,6-trihydroxyacetophenone, and their combination has been carried out systematically. The results show that a mixture of 2,4,6-trihydroxyacetophenone, 2,3,4-trihydroxyacetophenone and ammonium citrate with molar ratios of 2:1:1 serves as a good matrix for the detection of DNA, especially for samples containing a small quantity of DNA such as polymerase chain reaction product. The resolution and shot-to-shot reproducibility using this matrix are better than, and the MALDI sensitivity comparable to, that obtained when using 3-hydroxy picotinic acid (3-HPA), PA and ammonium citrate matrix (9:1:1). The mechanism of desorption/ionization using this matrix is discussed.

Base Sequence↗

Laser desorption mass spectrometry for point mutation detection.

A point mutation can be associated with the pathogenesis of inherited or acquired diseases. Laser desorption mass spectrometry coupled with allele specific polymerase chain reaction (PCR) was first used for point mutation detection. G551D is one of several mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene present in 1-3% of the mutant CFTR alleles in most European populations. In this work, two different approaches were pursued to detect G551D point mutation in the cystic fibrosis gene. The strategy is to amplify the desired region of DNA template by PCR using two primers that overlap one base at the site of the point mutation and which vary in size. If the two primers based on the normal sequence match the target DNA sequence, a normal PCR product will be produced. However, if the alternately sized primers that match the mutant sequence recognize the target DNA, an abnormal PCR product will be produced. Thus, the mass spectrometer can be used to identify patients that are homozygous normal, heterozygous for a mutation or homozygous abnormal at a mutation site. Another approach to identify similar mutations is the use of sequence specific restriction enzymes which respond to changes in the DNA sequence. Mass spectrometry is used to detect the length of the restriction fragments generated by digestion of a PCR generated target fragment.

Cell Line↗

Revisit of MALDI for small proteins.

Matrix-assisted laser desorption/ionization (MALDI) was used for several small proteins (such as insulin) and for peptides. It was found that the detection efficiencies of MALDI for the insulin B chain and the insulin A chain are drastically different. Similar phenomena were also observed for various types of peptides. The positive-ion signal of MALDI in detecting proteins or peptides was found to be greatly enhanced by the presence of a basic amino acid in their chains. The experimental results indicate that this enhancement may arise from proton transfer in solution by an acid-base reaction between the protein/peptide and matrix molecule. This pre-protonated mechanism provides a low energy barrier for the ionization of peptides in a MALDI process, and greatly reduces the energy threshold of MALDI. Matrix effects on the ionization mechanism are discussed.

Amino Acid Sequence↗

Picolinic acid as a matrix for laser mass spectrometry of nucleic acids and proteins.

We found that picolinic acid is a very good matrix for matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry of oligonucleotides, proteins and tRNA. Among the oligonucleotides, picolinic acid was shown to be effective for homo-oligonucleotides, d(G)40 and d(C)60, and for mixed-base oligonucleotides up to 190 bases. In the case of the single-stranded oligonucleotides, and of double-stranded ones as well, only parent ions corresponding to single-stranded DNA were observed. The efficiency for MALDI of oligonucleotides using the picolinic acid matrix was superior to that using 3-hydroxypicolinic acid. MALDI of transfer RNA phenylalanine-specific (tRNA(Phe)), a 76-base ribonucleic acid, was detected with a signal-to-noise ratio of > 10. By comparison with 3-hydroxypicolinic acid the results with picolinic acid are notably superior for all oligonucleotides.

Base Sequence↗

Detection of 500-nucleotide DNA by laser desorption mass spectrometry.

We report the first detection of DNA segments as large as 500 nucleotides by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, using picolinic acid and 3-hydroxypicolinic acid mixtures as desorption matrices. The successful detection of 500-nucleotide DNA indicates that laser mass spectrometry is now emerging as a new biotechnology tool for DNA-related research. It should be possible to utilize fast detection of large DNA segments by laser mass spectrometry for rapid human genome sequencing.

Base Sequence↗

3-Aminopicolinic acid as a matrix for laser desorption mass spectrometry of biopolymers.

3-Aminopicolinic acid (3-APA) was tested and found to be a useful matrix for matrix-assisted laser desorption/ionization of DNA and protein. Single-stranded DNA segments of 150-mer and double-stranded DNA of 246 base pairs were successfully detected by using 3-APA as an ultraviolet-absorbing matrix in a linear time-of-flight mass spectrometer. In the case of the double-stranded DNA, only parent ions corresponding to single-stranded DNA were observed. The comparison with 3-hydroxypicolinic acid and picolinic acid matrices is discussed.

Base Sequence↗