Applied Biosystems

About: Applied Biosystems is a based out in . It is known for research contribution in the topics: Mass spectrometry & Capillary electrophoresis. The organization has 1521 authors who have published 1579 publications receiving 285423 citations.

Automated mutation screening using dideoxy fingerprinting and capillary array electrophoresis.

Abstract: The rapid progress in the isolation of genes associated with human disease has resulted in an increasing demand for mutation screening methods. The molecular diagnosis of the long QT syndrome (LQTS), a cardiac disorder characterized by prolongation of the QT(c) interval in the ECG, syncopes, and sudden death, requires mutation screening of all exons in at least five genes, encoding cardiac Na(+) and K(+) channel subunits. A method for automated dideoxy fingerprinting (ddF) using capillary array electrophoresis (CAE) was developed and the efficiency of the method was tested by analyzing 24 DNA samples with mutations in one of the genes KCNQ1 and KCNH2, which are involved in 50% of LQTS cases. One of these mutations, 362insQK in KCNQ1, is novel. The sensitivity was 100% using a single electrophoresis temperature of 18 degrees C or 25 degrees C. However, analysis of the samples in both the sense and anti-sense direction were required for high sensitivity. Analysis in a single direction resulted in a decrease of the sensitivity to 74% and 70%, respectively. The throughput of the ddF method, if performed with a 16 capillary CAE instrument, is 288 samples per seven hr if each sample is analyzed on both strands.

On‐line negative ion liquid chromatography/mass spectrometry for the analysis of bile acids using low‐ and high‐resolution mass spetrometry

Abstract: Liquid chromatographic/mass spectrometric analysis of a mixture of bile acids has been carried out using a double-focusing mass spectrometer. A solution of polyethylene glycol was added post-column using a second pump and a micro vortex mixer. The mass spectrometer was tuned to give a 10 000 resolution, and mass measurement accuracies of greater than 3 mmu were obtained on-line.

Method of synthesizing sulfurized oligonucleotide analogs with thiuram disulfides

Abstract: A method for synthesizing sulfurized oligonucleotide analogs, such as phosphorothioate and phosphorodithioate analogs, is provided that employs a thiuram disulfide as a sulfurizing agent. The method of the invention may be used to sulfurize any phosphorous(III)-containing intermediate. Preferably, the method is practiced on a commercial DNA synthesizer using phosphoramidite and/or phosphorthioamidite intermediates.

A quantitative PCR method to detect blood microRNAs associated with tumorigenesis in transgenic mice

Abstract: MicroRNA (miRNA) dysregulation frequently occurs in cancer. Analysis of whole blood miRNA in tumor models has not been widely reported, but could potentially lead to novel assays for early detection and monitoring of cancer. To determine whether miRNAs associated with malignancy could be detected in the peripheral blood, we used real-time reverse transcriptase-PCR to determine miRNA profiles in whole blood obtained from transgenic mice with c-MYC-induced lymphoma, hepatocellular carcinoma and osteosarcoma. The PCR-based assays used in our studies require only 10 nanograms of total RNA, allowing serial mini-profiles (20 – 30 miRNAs) to be carried out on individual animals over time. Blood miRNAs were measured from mice at different stages of MYC-induced lymphomagenesis and regression. Unsupervised hierarchical clustering of the data identified specific miRNA expression profiles that correlated with tumor type and stage. The miRNAs found to be altered in the blood of mice with tumors frequently reverted to normal levels upon tumor regression. Our results suggest that specific changes in blood miRNA can be detected during tumorigenesis and tumor regression.

Method and apparatus for the identification and quantification of biomolecules

Abstract: Polypeptides are electroblotted through a digestion membrane to a composite capture membrane that can be directly analyzed using mass spectrometry. The molecular weights of the fragments generated by the digestion membrane are then used to identify the polypeptide from which they originated. The digestion membrane contains an immobilized protease such as trypsin, which cleaves the electroblotted polypeptides into fragments during electroblotting with such high enzyme cleavage capacity and efficiency that one pass of the polypeptide through the membrane is sufficient. The peptide fragments are collected onto a composite capture membrane that is chemically treated, for example by adding a mixture of nitrocellulose and MALDI matrix, so as to absorb peptides near the surface to facilitate desportion, thereby increasing the sensitivity of subsequent analysis by MALDI-TOF mass spectrometry. A wide variety of application are disclosed including identifying proteins separated on a gel or within a tissue sample.